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Main Differences Between Engravers & Marking Cutters

While similar on the surface, Half-round Engraving Cutters and Marking Cutters are actually very different. Both tools are unique in the geometries they possess, the benefits they offer, and the specific purposes they’re used for. Below are the key differences between Engraving Cutters and Marking Cutters that all machinists must know, as the engraving on a part is often a critical step in the machining process.

Engravers & Marking Cutters Serve Different Purposes

All Marking Cutters are Engraving Cutters, but not all Engraving Cutters are Marking Cutters. This is because Marking Cutters are a “type” of engraving tool. By virtue of their sturdier geometry, Marking Cutters are suited for applications requiring repetition such as the engraving of serial numbers onto parts. Harvey Tool has been able to customize specific tool geometries for ferrous and non-ferrous applications, offering Marking Cutters for material specific purposes.

engraver

Engraving Cutters, on the other hand, are meant for finer detailed applications that require intricate designs such as engraving a wedding band or a complex brand design.

engraver

These Tools Have Unique Geometry Features

Historically, Engraving Cutters have been made as a half round style tool. This tool allows for a true point, which is better for fine detail, but can easily break if not run correctly. Because of this, Engraving Cutters have performed well in softer materials such as aluminum and wood, especially for jobs that require an artistic engraving with fine detail.

Marking cutters are not as widely seen throughout the industry, however. These tools hold up in harder-to-machine materials exceedingly well. Marking Cutters are a form of Engraving Cutter that contain 2 flutes and a web at the tip, meaning that the tool has a stronger tip and is less susceptible to breakage.

engraver

While these tools do not contain a true point (due to their web), they do feature shear flutes for better cutting action and the ability to evacuate chips easier when compared to a half-round engraver.

Harvey Tool Product Offering

Harvey Tool offers a wide variety of both Engraving Cutters and Marking Cutters. Choose from a selection of pointed, double-ended, tip radius, and tipped-off Engraving Cutter styles in 15 included angles ranging from 10° to 120°.

engraver

Marking Cutters are fully stocked in tip radius or tipped-off options, and are designed specifically for either ferrous or non-ferrous materials. Marking Cutters are offered in included angles from 20° to 120°.

While Engraving Cutters are offered uncoated or in AlTiN, AlTiN Nano, or Amorphous Diamond coatings, Marking Cutters are fully stocked in uncoated, AlTiN, or TiB2 coated styles.

Marking Cutters & Engravers Summarized

While both Engraving Cutters and Marking Cutters can accomplish similar tasks, each tool has its own advantages and purpose. Selecting the correct tool is based largely on preference and applicability to the job at hand. Factors that could impact your selection would be final Depth of Cut, Width of Cut, the angle needing to be achieved, and the desired detail of the engraving.

Understanding Threads & Thread Mills

Thread milling can present a machinist many challenges. While thread mills are capable of producing threads with relative ease, there are a lot of considerations that machinists must make prior to beginning the job in order to gain consistent results. To conceptualize these features and choose the right tool, machinists must first understand basic thread milling applications.

 

What is a thread?

The primary function of a thread is to form a coupling between two different mechanisms. Think of the cap on your water bottle. The cap couples with the top of the bottle in order to create a water tight seal. This coupling can transmit motion and help to obtain mechanical advantages.  Below are some important terms to know in order to understand threads.

Root – That surface of the thread which joins the flanks of adjacent thread forms and is immediately adjacent to the cylinder or cone from which the thread projects.

Flank – The flank of a thread is either surface connecting the crest with the root. The flank surface intersection with an axial plane is theoretically a straight line.

Crest – This is that surface of a thread which joins the flanks of the thread and is farthest from the cylinder or cone from which the thread projects.

Pitch – The pitch of a thread having uniform spacing is the distance measured parallelwith its axis between corresponding points on adjacent thread forms in the same axial plane and on the same side of the axis. Pitch is equal to the lead divided by the number of thread starts.

Major Diameter – On a straight thread the major diameter is that of the major cylinder.On a taper thread the major diameter at a given position on the thread axis is that of the major cone at that position.

Minor Diameter – On a straight thread the minor diameter is that of the minor cylinder. On a taper thread the minor diameter at a given position on the thread axis is that of the minor cone at that position.

Helix Angle – On a straight thread, the helix angle is the angle made by the helix of the thread and its relation to the thread axis. On a taper thread, the helix angle at a given axial position is the angle made by the conical spiral of the thread with the axis of the thread. The helix angle is the complement of the lead angle.

Depth of Thread Engagement – The depth (or height) of thread engagement between two coaxially assembled mating threads is the radial distance by which their thread forms overlap each other.

External Thread – A thread on a cylindrical or conical external surface.

Internal Thread – A thread on a cylindrical or conical internal surface.

Class of Thread – The class of a thread is an alphanumerical designation to indicate the standard grade of tolerance and allowance specified for a thread.

Source: Machinery’s Handbook 29th Edition

Types of Threads & Their Common Applications:

ISO Metric, American UN: This thread type is used for general purposes, including for screws. Features a 60° thread form.

British Standard, Whitworth: This thread form includes a 55° thread form and is often used when a water tight seal is needed.

NPT: Meaning National Pipe Tapered, this thread, like the Whitworth Thread Form, is also internal. See the above video for an example of an NPT thread.

UNJ, MJ: This type of thread is often used in the Aerospace industry and features a radius at the root of the thread.

ACME, Trapezoidal: ACME threads are screw thread profiles that feature a trapezoidal outline, and are most commonly used for power screws.

Buttress Threads: Designed for applications that involve particularly high stresses along the thread axis in one direction. The thread angle on these threads is 45° with a perpendicular flat on the front or “load resisting face.”         

Thread Designations

Threads must hold certain tolerances, known as thread designations, in order to join together properly. International standards have been developed for threads. Below are examples of Metric, UN, and Acme Thread Designations. It is important to note that not all designations will be uniform, as some tolerances will include diameter tolerances while others will include class of fit.

Metric Thread Designations              

M12 x 1.75 – 4h – LH

In this scenario, “M” designates a Metric Thread Designation, 12 refers to the Nominal Diameter, 1.75 is the pitch, 4h is the “Class of Fit,” and “LH” means “Left-Hand.”

UN Thread Designations

¾ 10 UNC 2A LH

For this UN Thread Designation, ¾ refers to the thread’s major diameter, where 10 references the number of threads per inch. UNC stands for the thread series; and 2A means the class of thread. The “A” is used to designate external threads, while “B” is for internal threads. For these style threads, there are 6 other classes of fit; 1B, 2B, and 3B for internal threads; and 1A, 2A, and 3A for external threads.

ACME Thread Designations

A 1 025 20-X

For this ACME Thread Designation, A refers to “Acme,” while 1 is the number of thread starts. The basic major diameter is called out by 025 (Meaning 1/4”) while 20 is the callout for number of threads per inch. X is a placeholder for a number designating the purpose of the thread. A number 1 means it’s for a screw, while 2 means it’s for a nut, and 3 refers to a flange.

How are threads measured?

Threads are measured using go and no-go gauges. These gauges are inspection tools used to ensure the that the thread is the right size and has the correct pitch. The go gauge ensures the pitch diameter falls below the maximum requirement, while the no-go gauge verifies that the pitch diameter is above the minimum requirement. These gauges must be used carefully to ensure that the threads are not damaged.

Thread Milling Considerations

Thread milling is the interpolation of a thread mill around or inside a workpiece to create a desired thread form on a workpiece. Multiple radial passes during milling offer good chip control. Remember, though, that thread milling needs to be performed on machines capable of moving on the X, Y, and Z axis simultaneously.

5 Tips for Successful Thread Milling Operations:

1.  Opt for a Quality Tooling Manufacturer

There is no substitute for adequate tooling. To avoid tool failure and machining mishaps, opt for a quality manufacturer for High Performance Drills for your starter holes, as well as for your thread milling solutions. Harvey Tool fully stocks several types of threadmills, including Single Form, Tri-Form, and Multi-Form Thread Milling Cutters. In addition, the 60° Double Angle Shank Cutter can be used for thread milling.

thread milling

Image Courtesy of  @Avantmfg

2. Select a Proper Cutter Diameter

Choose only a cutter diameter as large as you need. A smaller cutter diameter will help achieve higher quality threads.

3. Ensure You’re Comfortable with Your Tool Path

Your chosen tool path will determine left hand or right hand threads.

Right-hand internal thread milling is where cutters move counterclockwise in an upwards direction to ensure that climb milling is achieved.

Left-hand internal thread milling a left-hand thread follows in the opposite direction, from top to bottom, also in a counterclockwise path to ensure that climb milling is achieved.

4. Assess Number of Radial Passes Needed

In difficult applications, using more passes may be necessary to achieve desired quality. Separating the thread milling operation into several radial passes achieves a finer quality of thread and improves security against tool breakage in difficult materials. In addition, thread milling with several radial passes also improves thread tolerance due to reduced tool deflection. This gives greater security in long overhangs and unstable conditions.

5. Review Chip Evacuation Strategy

Are you taking the necessary steps to avoid chip recutting due to inefficient chip evacuation? If not, your thread may fall out of tolerance. Opt for a strategy that includes coolant, lubricant, and tool retractions.

In Summary

Just looking at a threading tool can be confusing – it is sometimes hard to conceptualize how these tools are able to get the job done. But with proper understanding of call, methods, and best practices, machinists can feel confident when beginning their operation.

Form Factory – Featured Customer

Form Factory is a machine shop located in Portland, Oregon focused primarily on prototype work, taking 3D CAD models and making them a physical reality through CNC precision machining. Over the past 14 years, Form Factory has grown from a one man operation with a single CNC mill into a highly respected shop in the Northwest US, making prototype models for clients all over the world. Harvey Tool customers may recognize the name Form Factory from their photo on the front cover of the Fall 2018 Catalog, as they were the first place winners of the #MachineTheImpossible Catalog Cover Contest!

We talked with Brian Ross, Founder/Owner of Form Factory, to learn about how he suggests entrepreneurs and inventors think about prototyping their ideas, his unique experience working on many different models, his winning part in the #MachineTheImpossible contest, and more!

Thanks for taking the time to talk with us for this Featured Customer post. To get started, tell us a little bit about Form Factory, how you got started, and what sort of products you manufacture.

Prior to starting my own business, I had worked as a machinist at 4 different prototyping firms which is where I learned the trade and got the itch to run my own shop. I started Form Factory myself just over 14 years ago with a single Haas VF1. I had no client base and a bunch of loans. It was a scary time for me to jump in to entrepreneurship. Now, we have three CNC machines, various other components and machines, and four full-time employees.

At Form Factory we focus primarily on industrial design models and prototypes. We do a lot of work in the electronics industry, making prototypes of cell phones, laptops, printers, and other consumer electronics. Many of our models are created for display at trade shows or in Kickstarter and other product announcement videos, but we also do a fair share of working prototypes as well. It all depends on what the client wants, and we pride ourselves on the ability to deliver exactly what they need.

form factory

What sort of machines and software do you use in your shop?

We currently have 3 CNC mills – a Haas VF1, Haas VF2, and Haas VF3. We like using machines made in the USA because we like making products in the USA. Haas is what I knew and had run predominantly, and Haas is fairly common in the Northwest so it was easier to find skilled employees in the area who knew these machines well.

We use Mastercam for our CAM software, which is what I learned on. It also seems to be very common in this area which makes for an easy transition for new employees.

form factory

What were some of the keys to success as you built Form Factory from the ground up?

I based much of Form Factory’s business model on my past experiences in manufacturing. Many of the other small companies I had worked for ended up closing, even though the guys on the shop floor would be working lots of overtime and we had plenty of business. What I realized was that these other places often closed because of greed, over-expansion, and rapid growth which they could not sustain. They ended up overextending themselves and they could not keep the doors open as a result.

I like the spot I am in now because while we can certainly expand, we have found a happy medium. We have kept our customers happy and consistently deliver parts on time, so we get a lot of repeat business. Being a small company, word of mouth is one of our only forms of marketing. Word definitely gets around on how you treat people so we try to treat everyone with respect and honesty, which is key to running a good business.

form factory

Working Prototype of a “Smart Ball” Charger for Adidas

Prototype manufacturing is a very competitive segment of this industry. What sets Form Factory apart from the competition?

Understanding how model making relates to industrial design separates us from a typical machine shop. We can take a prototype design or simple drawing and we are able to implement all of the functionality into a prototype model. We do not deal much with the actual production run, which will come later, so we have the ability to focus more on the prototype and a customer’s exact needs to get a product off the ground. This level of expertise and focus sets us apart from your typical shop.

For example, if the model is for photography purposes, a trade show display, or a promotional video, appearance will be key. We will spend more time working on building what we consider to be a true work of art; something that will immediately stand out to the consumer, but may lack in complete functionality. If the client requires a fully functioning prototype, we will spend more time making sure that all of the components work as intended over multiple stages of design. The final result may be a bit “uglier” than a prototype designed for appearance alone, but it will work as intended.

Let’s say I have an idea for a new product. What should I know about getting my design manufactured?

Right now, especially with 3D printing and cheap overseas manufacturing, it can seem very easy to prototype a new product. However, these options are not always the best route to take to get a quality prototype. With 3D printing, you get a huge step down in resolution and quality, although you can save in cost. You can also save on cost by having things made overseas, but the communication can easily breakdown and the quality is often lower. The other factor is that virtually anyone can end up copying your product overseas and you have very little protection against that.

form factory

By going with a local machine shop and sticking with CNC-machined parts, you are guaranteed to get a higher quality finished product with better communication. We do a ton of back and forth communication with our clients to understand their exact design intent. With a prototype, there are often a lot of blanks that need to be filled in to completely understand the product, and we do our best to communicate with the client to deliver the perfect piece, and always on time. Sure, your cost may be higher, but the entire process will be smoother and the time saved on revisions or scrapping poor quality prototypes is invaluable.

It sounds like you guys take a lot of pride in the work you do, which is great!

Absolutely! Our models are all one of a kind works of art. We can take things from the early stages where a client might have an idea drawn on a napkin, all the way to a fully functional piece.

Our goal is always to make parts look like they grew that way. In my opinion, taking a solid block of material and making it into a finished part is truly a work of art. We work hard to determine where the burrs are, what the radiuses are, and how the finish should look, amongst many other variables. We take a lot of pride in the finished appearance and want everyone in the shop to produce the same level of quality as their co-workers. We hold all ourselves and our work to very high standards.

form factory

Finished Laptop Display Models

How has the online machinist community helped your business/changed your thinking/helped you grow as a machinist/business owner?

I follow tons of great machinists and other companies on Instagram.  It’s funny how quick you can get an idea from a simple picture or short video of another project somebody else is working on.  I love machining because after 25 years, I am still learning so much every day.  The machines, the software, and the tooling are changing so fast its hard to keep up.  Every day I see something on Instagram that makes me say “Oh WOW!” or “Hey, I can do my part that way!”  I was machining before there was an internet, so I really appreciate having an on-line community, and body of knowledge to draw from. You can find us on Instagram @FormFactory!

We loved the ball in chain part you created for our #MachineTheImpossible Fall 2018 Catalog Cover contest, and so did our followers, as they voted you into first place. Tell us a little more about that part.

So that piece was something I had been wanting to try for a while to challenge myself. It was not a part for a customer or part of a job, but simply a practice in more complex machining. The entire part was actually machined from one solid piece of aluminum on a 3 axis mill. With some clever fixturing and a few setups, I was able to make it work!

machine the impossible

Harvey Tool’s Tapered and Long Reach End Mills played a huge part in the creation. There would have been no way for me to get at those impossible angles or hard to reach areas without the multiple available dimensions and angles that you guys offer. In total, that piece took me about 20 hours, but it was a great piece to learn with and it definitely paid off in the end! As a small business, getting that exposure and marketing from being on your catalog cover was huge, and we appreciate the opportunity you gave us and the entire machinist community.

To a small business like yours, what did it mean to you to be highlighted on the Fall 2018 catalog cover?

I found out we had won when one of my customer’s emailed me congratulations! I was blown away! Even to be chosen as a finalist was exciting. The Harvey Tool Catalog is the ONE catalog we always have around the shop at the ready. I have been a Harvey fan for two decades, so making the cover of the catalog was pretty awesome!

In your career, how has Harvey Tool helped you #MachineTheImpossible?

Being able to overnight tools straight to the shop on a moment’s notice has saved us too many times to count. Harvey Tool makes some of the most impossible reach tooling; I still don’t know how they do it. ‘Back in the day” I would grind my own relief on an old Deckel. There’s nothing quite like looking for that extra 50 thou of reach and snapping off the tool! Now I let Harvey do ALL of that work for me, so I can focus on the machining. It takes nice tools to make nice parts. If you need tools that are always accurately relieved to just under the tool diameter, crazy sharp, and balanced, then look no further than Harvey Tool.

form factory

If you could give one piece of advice to a new machinist ready to take the #PlungeIntoMachining, what would it be?

Find the ‘Distance to Go’ setting or view on your machine’s control, and hit ‘feed hold’ with the first plunge of every new tool you set, and every new work offset, 100% of the time. It will save your mill and your parts from disaster. Machining is the art of doing thousands of simple things, exactly right and in the right order. The hard part is to keep your focus and pay keen attention through the entire process. Understand how easy it is to make a simple mistake, and how quickly you can be starting over. Allow yourself room for mistakes along the way by triple checking BEFORE your mill lets you know it’s too late. If you have other things on your mind, don’t machine parts.


Would you like to be considered for a future “Featured Customer” blog? Click here to submit your information.

University of Michigan Formula SAE Racing Team – Featured Customer

Formula SAE is a student design competition that began in 1980. The competition was founded by the SAE (Society of Automotive Engineers) branch at the University of Texas. Each year, hundreds of universities across the world spend months designing and manufacturing their best Formula style car before putting them to the test in competitions.

Alex Marshalek is the Team Captain of the University of Michigan’s Formula SAE team, MRacing. The team was originally founded in 1986, and has been very successful over the years. In the 2017 season, they finished 5th at the Formula SAE Michigan event, and took home a 1st place finish at Formula North. They are hoping to continue riding that momentum into another successful season in 2018.

Mracing

Alex reached out to Harvey Tool and Helical earlier this year, and after some conversation, the decision was made to sponsor their team’s efforts by supplying cutting tools and providing technical support. With competitions on the horizon and a new build coming over the summer, Alex was kind enough to find some time to talk with us about his experiences as a student learning the ropes in engineering, manufacturing, and design, the importance of quality tooling and maintaining a superior part finish for competition, and challenges he has faced during this process.

Hi Alex. Thanks for taking the time to talk with us today. When you were looking into college degree programs, what initially interested you in manufacturing and engineering?

I have always had an interest in Aerospace Engineering, but it was nothing more than a personal interest until I started college. My high school unfortunately did not have any machine shop or manufacturing type classes, so a lot of what I knew, I learned from my dad. My dad worked as a Mechanical Engineer at an axle manufacturing company, and he used to always be doing things around the house and showing me the basics of engineering and design.

When it came time to choose a school, I knew that Michigan had an impressive Aerospace Engineering department, and I liked the feel of the campus and community better than other schools I had toured.

How did you first get involved with the Formula SAE team?

I knew going into school that I wanted to get involved in a design team and advance my learning in that way. We have about a dozen different design teams at Michigan, but the Formula SAE team really stood out to me as a really cool project to get involved in.

I started with the team in Fall of 2016, helping out with the design and manufacturing of the vehicle’s suspension. Now, for the upcoming 2018 season, I am taking over the role of Team Captain. There will be a little bit less hands-on design and manufacturing work for me as it is more of an administrative/outreach role.

michigan racing

How does a typical FSAE season run?

So FSAE seasons are constantly running, and nearly overlapping with each other. For example, we are currently finishing up competitions from the 2018 season, but at the same time we are beginning the design of the vehicle for the 2019 season. Typically, the design work is done over the summer, and finalized in October. After that, the major manufacturing begins and lasts until about March, with spare parts and additions being added as we go. Testing begins in March, where we fine tune the vehicle and optimize the design for performance. Then, the rest of the Spring and early Summer is competition time, and the process starts all over again!

What sort of machines do you have in the shop?

Right now, we have three manual Bridgeport mills, two retro-fit CNC Bridgeport mills, 2 manual lathes, 1 retro-fit CNC lathe, and a Haas VF-2SS and Haas SL-20. For the vast majority of what we are machining, we are using the Haas. We do most of our work in Aluminum, with some parts made out of steel or titanium, and the Haas has been great for everything.

We are also using AutoDesk’s Fusion 360 software for our CAD/CAM, and we love it.

What has been the most difficult part of the build?

Time is really the biggest challenge. We are all full-time students, so time is already hard to find, but we also don’t have an overabundance of machinists so the operators can get overburdened. It all works out in the end and our machinists are great, but time management is truly the biggest challenge.

michigan formula sae

The composite materials we work with are also very challenging to machine. We constructed the vehicle’s monocoque (the structural “skin”, often seen in Formula One cars) out of carbon fiber. While we cut a lot of it on the water jet machine, we needed more precise holes than a water jet could offer, so we went to the Haas for that. We were using HSS drills and only getting 10-12 holes at a time before they wore out. However, we had Don Grandt (Harvey Performance Company Application Engineer) stop in the shop and he sent us a few Harvey Tool diamond coated drills, which should make this a much faster and more precise process!

You mentioned Don stopped in to give you guys a visit. What were some of your biggest takeaways?

Don was great. He stopped by and we gave him a tour of the facility and showed off some of the parts we were designing. We talked shop for quite a bit, and he gave us a bunch of great tips and tricks we could use to really optimize our machining. As I mentioned, he also went through the catalogs with us and helped us find exactly what we need for tooling. The Harvey Tool diamond coated drills are going to be a life saver for carbon fiber. I guess the biggest takeaway was just all of the knowledge we received from Don and how helpful that was to have someone direct from the tooling manufacturer sharing everything we knew with us.

Now that you have the Harvey and Helical tools in the shop, how have they helped you complete this project and get a leg up on your competition?

One of the most impressive things for us have been the finishing end mills we received. The Helical finishers for Aluminum are giving us some of the best finishes we have ever seen. For us, that is a point of pride. We not only want to have the fastest and most well-designed vehicle, but we also want to have the best looking parts. Subpar finishes reflect poorly on the entire build, and first impressions mean a lot in these competitions.

We have also been blown away by the Chipbreaker roughers. We absolutely love those tools and push them to the limits with great results. In fact, the first time we ran them, we used Machining Advisor Pro to dial in our speeds and feeds, and the numbers seemed insane to us. We were nervous, but we pushed the button and let it run. It was amazing to see that we could push a tool that fast without tool failure.

How has your experience been using Machining Advisor Pro?

We use Machining Advisor Pro every time we picked up the Helical end mills. MAP was actually one of the main reasons we were looking for Helical to sponsor us. We had heard a lot about MAP and your level of technical support, which was important to us as we are learning more about manufacturing and machining. Machining Advisor Pro has quickly become one of our best learning tools in the shop.

The nice thing about MAP is that is takes a look at all of the parameters. A lot of applications only give you numbers on your speeds and feeds, but MAP takes a look at the depth of cut, chip thinning, engagement angle, and all of the other parameters that are so essential to a successful run. As a result, we have been able to get very aggressive with the end mills. We are not a huge production shop, so cycle times are not as important, but we still want to get the most out of our tools in the least amount of possible time.

So, let’s break down some specs. What are you all working with on this year’s build?

Right now our car features a 4 cylinder Honda 600 CBR engine, with a Turbo and 600cc displacement. We are one of the few teams that run a turbo in competition. As we mentioned, the monocoque is completely carbon fiber, and the car features a full aero package with an undertray. The max speed is around 80 MPH, and the car weighs 420 pounds without the driver.

Once the build is complete, how does a typical competition work?

Most of the Formula SAE competitions are multi-day events, with a few static events, and then dynamic events where the car is running. For static events, we first have a Design portion. We validate and argue for our design in front of judges who are engineers in the industry. Then, we get into a Cost presentation, as one of the goals is to build the cheapest possible car with a high level of performance. That balance of cost vs. performance is a critical part of the build. The last static event is a Business presentation, where we introduce a business/manufacturing plan on how to get this design to a production level of 100 units in a year.

For the dynamic events, we have 4 different tests. First, we have the Accel Run, which is a 75 meter sprint, and the fastest cars win. From there we go to the Skip Pad event, which is centered on turning radius and the stiffness of the chassis as we do tight figure eight turns with the car.

University of Michigan FSAE

Then we have the AutoCross, a one lap race, which determines our placement in the final event; Endurance. For the Endurance event, we drive the cars around a 22km track, and the goal is to finish the race without any mechanical or design failures in the quickest time possible. Only around 50% of participants actually complete this event. If a single part falls off, or breaks, you are disqualified. Many times we see things like the suspension, powertrain, or wings falling off. It is disappointing when it happens, but it allows us to easily identify any flaws and fix them for the next event.

What is next for you after school? Any future plans or goals?

I am currently majoring in Aerospace Engineering, and would like to stay within that industry. I am leaning towards working on aircraft. Designing either aircraft structures or the aerodynamics would be very cool. I really like the size and scale of working on commercial aircraft, but I could see myself doing something more specialty like working in Defense as well.


Alex and his team had a very successful 2018 season. They recently placed 9th overall in a competition at the Michigan International Speedway. In the dynamic events, they placed 4th in Skidpad, and 7th in Autocross. The high placement in the Autocross event allowed them to race head to head against top teams in the world, and they ended up placing 4th in Endurance out of 104 cars!

The MRacing team also competed at Formula North, a competition in Ontario, Canada, where they achieved a top ranking of 2nd place overall. They passed all of the technical inspections on the first try and placed 1st in Acceleration, 2nd in Skidpad and Endurance, 3rd in Autocross, and 4th in Efficiency.

michigan fsae

Slaying Stainless Steel: Machining Guide

Stainless steel can be as common as Aluminum in many shops, especially when manufacturing parts for the aerospace and automotive industries. It is a fairly versatile material with many different alloys and grades which can accommodate a wide variety of applications. However, it is also one of the most difficult to machine. Stainless steels are notorious end mill assassins, so dialing in your speeds and feeds and selecting the proper tool is essential for machining success.

Material Properties

Stainless steels are high-alloy steels with superior corrosion resistance to carbon and low-alloy steels. This is largely due to their high chromium content, with most grades of stainless steel alloys containing at least 10% of the element.

Stainless steel can be broken out into one of five categories: Austenitic, Ferritic, Martensitic, Precipitation Hardened (PH), and Duplex. In each category, there is one basic, general purpose alloy. From there, small changes in composition are made to the base in order to create specific properties for various applications.

For reference, here are the properties of each of these groupings, as well as a few examples of the popular grades and their common uses.

Category Properties Popular Grades Common Uses
Austenitic Non-magnetic, outstanding corrosion and heat resistance. 304, 316 Food processing equipment, gutters, bolts, nuts, and other fasteners.
Ferritic Magnetic, lower corrosion and heat resistance than Austenitic. 430, 446 Automotive parts and kitchen appliances.
Martensitic Magnetic, moderate corrosion resistance – not for severe corrosion. 416, 420, 440 Knives, firearms, surgical instruments, and hand tools.
Precipitation Hardened (PH) Strongest grade, heat treatable, severe corrosion resistance. 17-4 PH, 15-5 PH Aerospace components.
Duplex Stronger mixture of both Austenitic and Ferritic. 244, 2304, 2507 Water treatment plants, pressure vessels.

Tool Selection

Choosing the correct tooling for your application is crucial when machining stainless steel. Roughing, finishing, slotting, and high efficiency milling toolpaths can all be optimized for stainless steel by choosing the correct style of end mill.

Traditional Roughing

For traditional roughing, a 4 or 5 flute end mill is recommended. 5 flute end mills will allow for higher feed rates than their 4 flute counterparts, but either style would work well for roughing applications. Below is an excellent example of traditional roughing in 17-4 Stainless Steel.

 

 

Slotting

For slotting in stainless steel, chip evacuation is going to be key. For this reason, 4 flute tools are the best choice because the lower flute count allows for more efficient chip evacuation. Tools with chipbreaker geometry also make for effective slotting in stainless steel, as the smaller chips are easier to evacuate from the cut.

stainless steel machining

Finishing

When finishing stainless steel parts, a high flute count and/or high helix is required for the best results. Finishing end mills for stainless steel will have a helix angle over 40 degrees, and a flute count of 5 or more. For more aggressive finishing toolpaths, flute count can range from 7 flutes to as high as 14. Below is a great example of a finishing run in 17-4 Stainless Steel.

 

High Efficiency Milling

High Efficiency Milling can be a very effective machining technique in stainless steels if the correct tools are selected. Chipbreaker roughers would make an excellent choice, in either 5 or 7 flute styles, while standard 5-7 flute, variable pitch end mills can also perform well in HEM toolpaths.

stainless steel

HEV-5

Helical Solutions offers the HEV-5 end mill, which is an extremely versatile tool for a variety of applications. The HEV-5 excels in finishing and HEM toolpaths, and also performs well above average in slotting and traditional roughing. Available in square, corner radius, and long reach styles, this well-rounded tool is an excellent choice to kickstart your tool crib and optimize it for stainless steel machining.

stainless steel machining

Running Parameters

While tool selection is a critical step to more effective machining, dialing in the proper running parameters is equally important. There are many factors that go into determining the running parameters for stainless steel machining, but there are some general guidelines to follow as a starting point.

Generally speaking, when machining stainless steels a SFM of between 100-350 is recommended, with a chip load ranging between .0005” for a 1/8” end mill up to .006” for a 1” end mill. A full breakdown of these general guidelines is available here.

Machining Advisor Pro

Machining Advisor Pro is a cutting edge resource designed to precisely calculate running parameters for high performance Helical Solutions end mills in materials like stainless steel, aluminum, and much more. Simply input your tool, your exact material grade, and machine setup and Machining Advisor Pro will generate fully customizable running parameters. This free resource allows you to push your tools harder, faster, and smarter to truly dominate the competition.

In Conclusion

Stainless steel machining doesn’t have to be hard. By identifying the proper material grade for each part, selecting the perfect cutting tool, and optimizing running parameters, stainless steel machining headaches can be a thing of the past.

Tips for Machining Gummy Materials

Machinists face many problems and challenges when manufacturing gummy materials. These types of materials include low carbon steels, stainless steels, nickel alloys, titanium, copper, and metals with high chromium content. Gummy materials have a tendency to produce long, stringy chips, and are prone to creating built-up edge. These common problems can impact surface finish, tool life, and part tolerances.

Continuous Chip With a Built-Up Edge

Continuous chips are long, ribbon-like chips that are formed when the tool cuts through a material, separating chips along the shear plane created by the tool’s cutting edge. These chips slide up the tool face at a constant flow to create a long and stringy chip. The high temperatures, pressures, and friction produced when cutting are all factors that lead to the sticky chips that adhere to the cutting edge. When this built up edge becomes large enough, it can break off leaving behind some excess material on the workpiece, or gouge the workpiece leaving a poor surface finish.

Coolant

Using large amounts of coolant can help with temperature control and chip evacuation while machining gummy materials. Temperature is a big driving force behind built-up edge. The higher the temperature gets, the easier and faster a built-up edge can form. Coolant will keep local temperatures lower and can prevent the material from work hardening and galling. Long, stringy chips have the potential to “nest” around the tool and cause tool failure. Coolant will help break these chips into smaller pieces and move them away from the cutting action by flash cooling them, resulting in fracturing of the chip into smaller pieces. Coolant should be applied directly to the contact area of the tool and workpiece to have the maximum effect.

Tool Engagement

Running Parameters

The tool should be constantly fed into the workpiece. Allowing the tool to dwell can cause work hardening and increase the chance of galling and built up edge. A combination of higher feed rates and lower speeds should also be used to keep material removal rates at a reasonable level. An increase in feed rates will raise the temperature less than an increase in speed. This relates to chip thinning and the ability of a tool to cut the material rather than rub against it.

Climb Milling

Climb milling is the preferred method as it directs more heat into the chip than the tool. Using climb milling, the largest chip cross section is created first, allowing the tool to cut through the material much easier. The heat generated from friction when the tool penetrates the workpiece is transferred to the chip rather than the tool because the thickest part of the chip is able to hold more heat than the thinnest.

climb milling

Initial Workpiece Engagement

Sudden, large changes in force, like when a tool initially engages a workpiece, have a negative impact on tool life. Using an arc-in tool path to initially engage the material allows for increased stability with a gradual increase in cutting forces and heat. A gradual tool entry such as this is always the preferred method over an abrupt straight entry.

Tool Selection

A tool with a sharp and robust cutting edge should be selected to machine gummy materials. Helical has tooling specifically designed for Titanium and Stainless Steel to make your tool selection process easy.

Additionally, choosing a tool with the correct coating for the material you are machining will help to protect the cutting edge and result in a far lower chance of built up edge or galling than an uncoated tool. A tool with a higher flute count can spread tool wear out over multiple cutting edges, extending tool life. Tool wear is not always linear in gummy materials; as soon as a little bit of wear appears, tool failure will happen relatively quickly. Changing the tool at the first sign of wear may be necessary to ensure that parts are not scrapped.

Gummy Materials Summarized

Every material machines somewhat differently, but understanding what is happening when the tool cuts the workpiece and how this affects tool life and finish will go a long way to successfully completing any job.  Built-up edge and excess heat can be minimized by selecting the correct tool and coating for the material, and following the tips and techniques mentioned above. Finally, be sure to check your machine’s runout and ensure maximum rigidity prior to beginning your machining operation.

Tool Deflection & Its Remedies

Every machinist must be aware of tool deflection, as too much deflection can lead to catastrophic failure in the tool or workpiece. Deflection is the displacement of an object under a load causing curvature and/or fracture.

For Example: When looking at a diving board at rest without the pressure of a person’s weight upon it, the board is straight. But as the diver progresses down further to the end of the board, it bends further. Deflection in tooling can be thought of in a similar way.

Deflection Can Result In:

  • Shortened tool life and/or tool breakage
  • Subpar surface finish
  • Part dimensional inaccuracies

Tool Deflection Remedies

Minimize Overhang

Overhang refers to the distance a tool is sticking out of the tool holder. Simply, as overhang increases, the tool’s likelihood of deflection increases. The larger distance a tool hangs out of the holder, the less shank there is to grip, and depending on the shank length, this could lead to harmonics in the tool that can cause fracture. Simply put, For optimal working conditions, minimize overhang by chucking the tool as much as possible.

extended reach tool

Image Source: @NuevaPrecision

Long Flute vs. Long Reach

Another way to minimize deflection is having a full grasp on the differences between a long flute and a long reach tool. The reason for such a difference in rigidity between the two is the core diameter of the tool. The more material, the more rigid the tool; the shorter the length of flute, the more rigid the tool and the longer the tool life. While each tooling option has its benefits and necessary uses, using the right option for an operation is important.

The below charts illustrate the relationship between force on the tip and length of flute showing how much the tool will deflect if only the tip is engaged while cutting. One of the key ways to get the longest life out of your tool is by increasing rigidity by selecting the smallest reach and length of cut on the largest diameter tool.

tool deflection

 

tool deflection

 

When to Opt for a Long Reach Tool

Reached tools are typically used to remove material where there is a gap that the shank would not fit in, but a noncutting extension of the cutter diameter would. This length of reach behind the cutting edge is also slightly reduced from the cutter diameter to prevent heeling (rubbing of noncutting surface against the part). Reached tools are one of the best tools to add to a tool crib because of their versatility and tool life.

 

When to Opt for a Long Flute Tool

Long Flute tools have longer lengths of cut and are typically used for either maintaining a seamless wall on the side of a part, or within a slot for finishing applications. The core diameter is the same size throughout the cutting length, leading to more potential for deflection within a part. This possibly can lead to a tapered edge if too little of the cutting edge is engaged with a high feed rate. When cutting in deep slots, these tools are very effective. When using HEM, they are also very beneficial due to their chip evacuation capabilities that reached tools do not have.

 

Deflection & Tool Core Strength

Diameter is an important factor when calculating deflection. Machinists oftentimes use the cutter diameter in the calculation of long flute tools, when in actuality the core diameter (shown below) is the necessary dimension. This is because the fluted portion of a tool has an absence of material in the flute valleys. For a reached tool, the core diameter would be used in the calculation until its reached portion, at which point it transitions to the neck diameter. When changing these values, it can lower deflection to a point where it is not noticeable for the reached tool but could affect critical dimensions in a long flute tool.

Deflection Summarized

Tool deflection can cause damage to your tool and scrap your part if not properly accounted for prior to beginning a job. Be sure to minimize the distance from the tool holder to the tip of the tool to keep deflection to a minimum. For more information on ways to reduce tool deflection in your machining, view Diving into Depth of Cut.

Attacking Aluminum: A Machining Guide

Aluminum is one of the most commonly machined materials, as most forms of the material feature excellent machinability, and is thus a commonly used material in manufacturing. Because of this, the competition for aluminum machining can be intense. Understanding the basics behind tool selection, running parameters, and advanced milling techniques for aluminum can help machinists earn a competitive advantage.

Material Properties

Aluminum is a highly formable, workable, lightweight material. Parts made from this material can be found in nearly every industry. Additionally, Aluminum has become a popular choice for prototypes due to its low-cost and flexibility.

Aluminum is available in two basic forms: Cast and Wrought. Wrought Aluminum is typically stronger, more expensive, and contains a lower percentage of outside elements in its alloys. Wrought Aluminum is also more heat-resistant than Cast and has a higher level of machinability.

Cast Aluminum has less tensile strength but with a higher flexibility. It costs less, and has higher percentages of outside elements (silicon, magnesium, etc.) in its alloys, making it more abrasive than Wrought.

Tool Geometry

There are a few coating options available for Aluminum tooling, including the popular gold-colored ZrN (Zirconium Nitride) and the lesser known but highly effective TiB2 (Titanium Diboride). Uncoated tooling can also provide solid machining performance. However, the real key to high performance machining in Aluminum is knowing the proper flute count and helix angle required for your operation.

Flute Count

End mills for aluminum are often available in either 2 flute or 3 flute styles. With higher flute counts, it would become difficult to evacuate chips effectively at the high speeds at which you can run in aluminum. This is because aluminum alloys leave a large chip, and chip valleys become smaller with each additional flute on an end mill.

flute count for aluminum

Traditionally, 2 flute end mills have been the preferred choice for Aluminum. However, 3 flute end mills have proven to be more successful in many finishing operations, and with the right parameters they can also work successfully as roughers. While much of the debate between 2 and 3 flute end mills for Aluminum boils down to personal preference, the operation, rigidity, and desired material removal rates can also have an effect on tool selection.

Helix Angles

The helix angle of a tool is measured by the angle formed between the centerline of the tool and a straight line tangent along the cutting edge. Cutting tools for aluminum typically feature higher helix angles than standard end mills. Specialized helix angles for Aluminum are typically either 35°, 40°, or 45°. Variable helix tools are also available and make a great choice for reducing chatter and harmonics while also increasing material removal rates.

Aluminum Machining

A helix angle of 35° or 40° is a good choice for traditional roughing and slotting applications. A 45° helix angle is the preferred choice for finishing, but also for High Efficiency Milling toolpaths as the high helix angle wraps around the tool faster and makes for a more aggressive cut.

Tooling Options

When machining aluminum, standard 2 or 3 flute tools will often get the job done. However, for certain applications and machine setups there are some more tooling options to consider for even better performance.

Chipbreaker Tooling

One of the most important things to consider when machining aluminum (and many other materials) is effective chip evacuation. Standard 2-3 flute end mills running at recommended speeds and feeds and proper chip loads can evacuate chips fairly well. However, 3 flute chipbreaker tooling can run at increased speed and feed rates for even better performance. The unique offset chip breaker geometry creates smaller chips for optimal evacuation while still leaving a semi-finished surface.

Chipbreaker Aluminum

These tools are excellent for more advanced toolpaths like High Efficiency Milling, which is another important tool for a successful aluminum machining experience.

High Balance End Mills

High balance end mills are designed to significantly increase performance in highly balanced machining centers capable of elevated RPMs and feed rates. These tools are precision balanced specifically for high velocity machining in aluminum (up to 33,000 RPM).

High Balance Tools for Aluminum

Helical Solutions offers high balance tooling in standard 2 flute styles, as well as coolant-through 3 flute styles for reduced heat, enhanced chip evacuation, and increased material removal rates. These tools, like the chipbreakers, are also an excellent choice for High Efficiency Milling toolpaths.

Running Parameters

Setting the right parameters for aluminum applications is vital to optimizing productivity and achieving better machining results. Since aluminum is an easier material to machine, pushing your machine to its limits and getting the most out of your tool is vital to stay ahead of the competition and keep winning business.

While there are many factors that go into the parameters for every job, there are some general guidelines to follow when machining aluminum. For cast aluminum alloys (i.e. 308, 356, 380), a surface footage of 500-1000 SFM is recommended, with RPMs varying based on cutter diameter. The basic calculation to find a starting point for RPMs would be (3.82 x SFM) / Diameter.

In wrought aluminum alloys (i.e. 2024, 6061, 7075), a surface footage of 800-1500 SFM is recommended, with the same calculation being used to find a starting point for RPMs.

High Efficiency Milling

High Efficiency Milling, commonly known as HEM, is a strategy that is rapidly gaining popularity in the manufacturing industry. Many CAM programs are now including HEM toolpaths, and while virtually any machine can perform HEM, the CNC controller must feature a fast processor to keep up with the additional lines of code. A great example of High Efficiency Milling toolpaths in Aluminum can be seen below.

At its core, HEM is a roughing technique that utilizes a low Radial Depth of Cut (RDOC) and a high Axial Depth of Cut (ADOC) to take full advantage of the cutting edge of the tool. To learn more about how High Efficiency Milling can increase your efficiency, extend your tool life to keep costs down, and get greater performance for aluminum (and other materials), click here to download the HEM Guidebook.

In Summary

Aluminum is a versatile material with a high level of machinability, but it should not be overlooked. Understanding the best ways to tackle it is important for achieving the desired results. Optimizing your tool crib, machine setups, and toolpaths for aluminum is essential to stay ahead of the competition and make your shop more efficient.

Why You Should Stop Deburring By Hand

Deburring is a process in which sharp edges and burrs are removed from a part to create a more aesthetically pleasing final product. After milling, parts are typically taken off the machine and sent off to the Deburring Department. Here, the burrs and sharp points are removed, traditionally by hand. However, an operation that takes an hour by hand can be reduced to mere minutes by deburring parts right in the machine with high precision CNC deburring tools, making hand deburring a thing of the past.

High Precision Tools

Hand deburring tools often have a sharp hook-shaped blade on the end, which is used to scrape/slice off the burrs as it passes along the edge of the part. These tools are fairly simple and easy to use, but much less efficient and precise than CNC deburring tools.

hand deburring

Image Source: https://upload.wikimedia.org/wikipedia/commons/0/03/Deburring_tool.jpg

CNC deburring tools are also held to much tighter tolerances than traditional hand-deburring tools. Traditional cylindrical deburring tools typically have a diameter-tolerance window of +/- .008 versus a CNC deburring end mill which has a diameter tolerance of +/-.0005. The tighter tolerance design eliminates the location issues found in traditional deburring tools with loose tolerances, allowing them to be programmed like a traditional end mill.

While hand deburring tools often have just a single blade, CNC deburring tools feature double cut patterns and a high number of flutes. The double cut pattern contains both right hand and left hand teeth, which results in an improved finish. These tools leave completed parts looking far superior to their hand-deburred counterparts, with more consistent and controlled edge breaks. Additionally, there is a large variety of CNC deburring tools available today which can take full advantage of multi-axis machines and the most complex tool paths. For example, Harvey Tool’s 270° Undercutting End Mill is a great choice for multi-axis and more complex deburring options. Further, Deburring Chamfer Cutters are multi-use tools that can perform both chamfering and deburring accurately with no need for a tool change.

cnc deburring

Reduce Production Costs and Increase Profits

Having an entire department dedicated to deburring can be costly, and many smaller businesses may have pulled employees off other jobs to help with deburring, which hampers production. Taking employees off the deburring station and asking them to run more parts or man another department can help keep labor costs low while still increasing production rates.

cnc deburring

Stop Deburring By Hand and Increase Your Profits

By deburring right in the CNC machine, parts can be completed in one machining operation. The double-cut pattern found on many deburring tools also allows for increased speeds and feeds. This helps to reduce cycle times even further, saving hours of work and increasing production efficiency. Deburring in the machine is a highly repeatable process that reduces overall cycle times and allows for more efficient finishing of a part. In addition, CNC machines are going to be more accurate than manual operations, leading to fewer scrapped parts due to human error and inconsistencies.

Simply put, the precision and accuracy of the CNC machine, along with the cost and time savings associated with keeping the part in the machine from start to finish, makes deburring in the CNC machine one of the easiest way to increase your shop’s efficiency.

5 Ways Your Shop is Inefficient

5 Ways Your Shop is Inefficient

In today’s ultracompetitive industry, every machine shop seeks even the slightest edge to gain an advantage on their competition and boost their bottom line. However, what many machinists don’t know is that improving their shop’s efficiency might be easier than they thought. The following five ways your shop is inefficient will provide a clear starting point of where to look for machinists desperate to earn a competitive edge.

1. Premature Tool Decay / Tool Failure

If you’re finding that your tools are failing or breaking at an unacceptable rate, don’t mistake it for commonplace. It doesn’t have to be. Prolonging the life of your tooling starts with finding not just the right tool, but the best one; as well as running it in a way to get its optimal performance. Many machinists mistake premature tool failure with running parameters that were too aggressive. In fact, not pushing the tool to its full potential can actually cause it to decay at an accelerated rate in certain situations.

Tool failure can occur in many different ways: Abrasive Wear, Chipping, Thermal Cracking or Tool Fracture, just to name a few. Understanding each type and its causes can help you to quickly boost your shop’s efficiency by minimizing downtime and saving on replacement tool costs.

tool wear

An example of a tool with excessive wear

For more information on tool wear, view Avoiding 4 Major Types of Tool Wear.

2. Subpar Part Finish

Your shop spends money to employ machinists, run machines, and buy cutting tools. Get your money’s worth, lead the industry, and ensure that you’re providing your customers with the highest quality product. Not only will this help to keep your buyer-seller relationship strong, but it will allow you the flexibility to increase your prices in the future, and will attract prospective customers.

Many factors influence part finish, including the material and its hardness, the speeds and feeds you’re running your tool at, tool deflection, and the tool-to-workpiece orientation.

For more information on ways to improve your part finish, view our Part Finish Reference Guide.

3. Inefficient Coolant Usage

One often forgotten expense of a machine shop is coolant – and it can be pricey. A 55-gallon drum of coolant can run more than $1,500. What’s worse is that coolant is often applied in excess of what’s required for the job. In fact, some machines even feature a Minimum Quantity Lubricant (MQL) functionality, which applies coolant as an extremely fine mist or aerosol, providing just enough coolant to perform a given operation effectively. While drowning a workpiece in coolant, known as a “Flood Coolant,” is sometimes needed, it is oftentimes utilized on jobs that would suffice with much less.

For more information about coolants and which method of application might be best for your job, view What You Need to Know About Coolant for CNC Machining.

4. Not Taking Advantage of Tool Versatility

Did you know that several CNC cutting tools can perform multiple operations? For example, a Chamfer Mill can chamfer, bevel, deburr, and countersink. Some Chamfer Mills can even be used as a Spotting Drill. Of course, the complexity of the job will dictate your ability to reap the benefits of a tool’s versatility. For instance, a Spotting Drill is obviously the best option for spotting a hole. If performing a simple operation, though, don’t go out of your way to buy additional tooling when what’s already in your carousel can handle it.

chamfer mills

To learn more about versatile tools that can perform multiple applications, check out Multi-Functional Tools Every Shop Should Have.

5. High Machine Downtime

What use is a machine that’s not running? Minimizing machine downtime is a key way to ensure that your shop is reaching its efficiency pinnacle. This can be accomplished a variety of ways, including keeping like-parts together. This allows for a simple swap-in, swap-out of material to be machined by the same cutting tool. This saves valuable time swapping out tooling, and lets your machine to do its job for more time per workday. Production planning is a key factor to running an efficient machine shop.