Drilling an ultra-precise hole can be tough. Material behavior, surface irregularities, and drill point geometry can all be factors leading to inaccurate holes. A Spot Drill, if used properly, will eliminate the chance of drill walking and will help to ensure a more accurate final product.
Ideally, the center of a carbide drill should always be the first point to contact your part. Therefore, a spotting drill should have a slightly larger point angle than that of your drill. If a spotting drill with a smaller point angle than your drill is used, your drill may be damaged due to shock loading when the outer portion of its cutting surface contacts the workpiece before the center. Using a drill angle equal to the drill angle is also an acceptable situation. Figure 1 illustrates the desired effect. On the left, a drill is entering a previously drilled spot with a slightly larger angle than its point. On the right, a drill is approaching an area with an angle that is far too small for its point.
Marking Your Spot
A Spotting Drill’s purpose is to create a small divot to correctly locate the center of a drill when initiating a plunge. However, some machinists choose to use these tools for a different reason – using it to chamfer the top of drilled holes. By leaving a chamfer, screw heads sit flush with the part once inserted.
What Happens if I Use a Spot Drill with an Improper Angle?
Using a larger angle drill will allow the drill to find the correct location by guiding the tip of the drill to the center. If the outer diameter of a carbide drill were to contact the workpiece first, the tool could chip. This would damage the workpiece and result in a defective tool. If the two flutes of the drill were slightly different from one another, one could come into contact before the other. This could lead to an inaccurate hole, and even counteract the purpose of spot drilling in the first place.
Avoiding CNC Drill Walking With a Spotting Drill
Few CNC machining applications demand precision like drilling. The diameter hole size, hole depth, part location, and finish are all important and provide little recourse if not up to specifications. That said, accuracy is paramount – and nothing leads to inaccurate final parts faster than drill walking, or the inadvertent straying from a drill’s intended location during the machining process. So how does drill walking occur, and how can one prevent it?
To understand drill walking, think about the act of striking a nail with a hammer, into a piece of wood. Firm contact to a sharp nail into an appropriate wood surface can result in an accurate, straight impact. But if other variables come into play – an uneven surface, a dull nail, an improper impact – that nail could enter a material at an angle, at an inaccurate location, or not at all. With CNC Drilling, the drill is obviously a critical element to a successful operation – a sharp, unworn cutting tool – when used properly, will go a long way toward an efficient and accurate final part.
To mitigate any variables working against you, such as an uneven part surface or a slightly used drill, a simple way to avoid “walking” is to utilize a Spotting Drill. This tool is engineered to leave a divot on the face of the part for a drill to engage during the holemaking process, keeping it properly aligned to avoid a drill from slipping off course.
When Won’t a Spot Drill Work for My Application?
When drilling into an extremely irregular surface, such as the side of a cylinder or an inclined plane, this tool may not be sufficient to keep holes in the correct position. For these applications, flat bottom versions or Flat Bottom Counterbores may be needed to creating accurate features.
https://www.harveyperformance.com/wp-content/uploads/2017/03/Feature-Image-Spotting-Drills-IMG.jpg5251400Tom Pylehttp://www.harveyperformance.com/wp-content/uploads/2018/08/Logo_HarveyPerformanceCompany-4.pngTom Pyle2022-08-25 10:52:002022-08-25 10:52:07Spot Drilling: the First Step to Precision Drilling
An end mill has an expected lifespan determined by its usage, material specificity, and coating. For machinists, premature wear and tool breakage are easily avoidable headaches. These issues can lead to poor part finishes, machine downtime, and even scrapped parts. Understanding the problems these tools face in the spindle is a key first step in troubleshooting these issues, if they occur.
Premature Tool Wear
Premature tool wear in end mills is one of the most common issues a machinist will face. Tool wear is often an issue when cutting speeds are faster than recommended for the tool, or, interestingly enough, when the speed and/or feed of the end mill is too light.
In addition, hard and naturally abrasive materials wreak havoc on cutting tools when proper tool coatings are not utilized. Coatings play a myriad of roles for a cutting tool, and cutting operation, including providing wear resistance and aiding in the efficiency of chip removal.
Other common causes of premature wear include the usage of incorrect helix angles, or chip re-cutting.
Solving these problems is quite straightforward. In the cases of cutting speeds and feeds being incorrect, machinists have several options. First decreasing the spindle speed will correct cutting speeds being too fast. Secondly, adjusting speeds and feeds by consulting with the manufacturers speeds and feeds charts will allow for proper tool usage. This will also solve chip re-cutting issues, and will adjust depth of cut (DOC) and/or coolant/air to properly clear chips from the part. Finally, selecting the proper helix angle and coating for the job will get the best lifespan and performance out of the cutting tool.
End Mill Edge Chipping
End mill edge chipping is commonly seen within aggressive and rigid machining. Machinists will find this when their feed rate is too aggressive in both the continued machining and on initial cut. Aggressive DOC is another common cause of tool chipping.
Edge chipping is an easily solved issue for machinists. Reducing the overall and initial feed rate will decrease the aggressiveness of the cut. Decreasing axial and/or radial depth of cut is another solution for overly aggressive tool paths.
Regarding rigidity, if the tool itself is the issue, machinists should change their tool holder, hold the tool shank deeper, or use a shorter tool. Re-fixturing the workpiece and/or improving the overall setup can also solve this problem. Lastly, machinists should check their spindle for run-out.
Much like edge chipping, tool breakage can occur during aggressive feed rates and excessive depths of cut. Similarly, extreme tool overhang is a major driver in tool breakage. Chip packing is also commonly found during a tool fracture and breakage. Another primary cause of breakage is found when an end mill is excessively worn.
Reducing feed rate and axial/radial DOC is crucial to solving tool breakage issues. This shows the machinist that their tool paths are too aggressive for the structure of the chosen tool. For issues related to overhang, a machinist should hold their shank deeper or even opt for a shorter tool.
There are several solutions for chip packing that include adjusting speeds and feeds, and increasing coolant or air pressure to properly flush chips. Tools with fewer flutes and deeper valleys flush chips much easier. In this case, opting for a tool with fewer flutes can also combat chip packing. Finally, choosing to regrind a tool sooner will solve tool breakage due to excessive wear.
As chip packing is a driver for tool breakage, solving this issue early is key to machining success. This is caused by aggressive speeds and feeds that are beyond the tool’s capabilities. Also, flute gullets that are too small for the produced chips will lead to packing. Finally, insufficient coolant volume and pressure won’t allow for chips to properly evacuate.
To start, machinists should consult the manufacturers’ speeds and feeds charts for the tool and consider decreasing them. Using an end mill with fewer flutes will prevent packing by allowing chips to properly evacuate. Increasing coolant volume and pressure, along with repositioning the nozzle closer to the point of cut, will also aid in proper evacuation.
Tool chatter, or chattering, is an easy way to scrap a part in the machine. Chattering can occur prior to breakage, so the solutions to these problems are very similar. While it is not possible to completely avoid vibrations, minimizing them is pivotal for a successful machining operation.
Rigidity and aggressive toolpaths are common in issues of tool chatter at the spindle. This lacking of rigidity is not limited to the tool itself, but can also be attributed to instances in the workpiece and machine tool. Also, choosing improper tool geometry can lead to instances of unnecessary vibrations.
Reducing speeds and feeds, as well as axial and/or radial DOC, is pivotal in solving tool chatter issues. When poor rigidity is the cause, machinists must determine where this is coming from. Changing the tool holder, holding the shank deeper, and using a shorter tool will often solve these issues. Machinists should also check their spindle for run out in cases of rigidity. Finally, re-fixturing the workpiece and/or improving the overall setup will help if that is the cause.
Burs are common in machining and cause machinists to painstakingly hand deburr a part after completion. While this is common, there are several causes for excessive burs in a part. First, incorrect speeds and feeds in machining can cause burs, as can dull end mill edges and incorrect helix angles.
If burs are present in machining, one should first start by consulting proper speeds and feeds for a tool, and consider decreasing them during machining. Finally, using a climb milling machining strategy, and changing to the correct helix angle, will pay off.
Proper part finish is crucial to success for all machinists. On the other hand, poor part finish often leads to scrapped parts and headaches. This is usually caused by feed rates that are too aggressive and speeds that are too slow for the tool and material. In terms of feed rates, aggressive depths of cut mark up parts, leading to poor finishes. Finally, properly sharpened tools in perfect scenarios lead to fantastic finishes. When tools face excessive wear, the part finish will suffer.
Reducing feed rates and depths of cut is critical to ensuring a proper part finish. Increasing tool speed (RPM) will also aid in leaving a better finish on the part. Finally, using a properly sharp, or timely reground tool, will alleviate part finish headaches.
Poor Dimensional Accuracy
Accuracy of part dimensions is paramount to a machinist’s and shop’s success. When poor dimensional accuracy is plaguing a job, there are several areas machinists should investigate. Aggressive depths of cut, tool rigidity, and machine tool rigidity are all common causes of inaccuracy.
Reducing axial and/or radial depths of cut is an important first step towards solving dimensional accuracy problems. If a lack of rigidity is the issue, a machinist should check, inspect, and repair the machine, tool, tool holder, and fixtures. Also, using a tool with more flutes can solve for this issue.
Overall, there are several milling issues that can impact even the most seasoned machinists. Properly identifying the problem is a critical first step in accounting for these problems. Once the problem has been identified, understanding the leading cause behind it will lead to understand the proper solution.
When navigating Titan USA’s offering of carbide drills, it is imperative to understand the key differences among the three carbide drill styles: Jobber Length, Stub Length, and Straight Flute Drills. The right drill for your application depends on, among other factors, the material you are working in, the job requirements, and the required accuracy.
Chip evacuation can be an obstacle for hole making. Pecking cycles can be used to aid in chip removal. Peck cycles are when the drill is brought in and out of the hole location, increasing depth each time until the desired depth is reached. However, pecking cycles should only be used when necessary; this process increases cycle time and subjects the tool to added wear from the repeated engaging and disengaging.
Jobber Length Drills
A carbide Jobber Length Drill is the standard general-purpose drill within Titan USA’s offering. It has a long flute length and an included angle of 118o. These drills are great for general purpose drilling where the tolerances are not as tight as the Stub Drill or Straight Flute Drill. Due to the length of these drills, however, they will be more affected by any lack of rigidity in the set up and can have higher runout, or straying from a desired location, during the drilling operation.
To achieve high accuracy and great finish, consider utilizing a Reamer. Reamers are designed to remove a finite amount of material but bring a hole to a very specific size. To do this, first drill 90% – 94% of the desired hole diameter with a Jobber Drill. After 90% – 94% of the material is removed, go in for a finishing pass with a Reamer. Reaming tools are highly accurate and leave a beautiful finish.
Stub Length Drills
Titan USA carbide Stub Length Drills have a shorter flute length, wider included point angle, and a significant drop in helix angle, when compared to Jobber Length Drills. The shorter length and wider tip create for a more rigid tool and, in turn, more accurate holes. The stub drill is the best option when drilling with tight tolerances on shallower holes.
Straight Flute Drills
Carbide Straight Flute Drills have the smallest core of the three drill types mentioned within this post. Titan USA offers Straight Flute Drills with 2 flutes and a 140o included angle. These drills are designed for hole making in materials that create short chips. Materials in which the Straight Flute Drill typically performs best include cast aluminums and cast irons, as well as copper. In addition, this type of drill can work very well in high hardness materials, but the core diameter should first be adjusted to accommodate the increased hardness. For these difficult to machine materials, casting the part with a core hole and then opening it up with the Straight Flute is a great option. This removes some of the stress caused by chip removal and allows for the drill to do what it does best.
Chip removal can be more difficult in this style of carbide drill because the chips are not guided along a helix. With helix flutes, the motion of chip removal is mostly continuous from their initiation point, through the flute valleys, and finally out of the flute valleys. The helix creates a wedge which helps push the chips along, but the straight flute does not have that. It interrupts that natural turning motion created by the drill face which can affect chip evacuation. Due to the interruption in motion this type of drill is better suited for applications involving chips of smaller size.
Helix drills create multiple different forces on the part, which can create micro imperfections. The Straight Flute Drills do not create those forces, so the finish is much more consistent down to the micro level. The margins of the Straight Flute Drill also burnish the inside of the hole as they spin, which improves the finish as well. When comparing the Straight Flute Drill to a helix drill, the length of the overall contact point is much shorter in the Straight Flute Drill, and has less heat generation. The decreased heat will also reduce the probability of work hardening.
Selecting Your Perfect Titan USA Carbide Drill
Selecting the correct carbide drill for your application is a crucial step in hole making. The Jobber Drill is a great general-purpose drill and should be utilized in applications requiring long reach. The Stub Drill increases the rigidity with its shorter length of flute, allowing it to drill with higher accuracy. Applications which involve tight tolerances and more shallow holes can be done with the Stub Drill for high-quality results. Lastly, for difficult to machine and hard materials, the Straight Flute Drill is the perfect solution. When the core diameter and chip evacuation is properly addressed, the Straight Flute Drill produces beautifully consistent surface finish and extremely tight tolerances. Similarly, Titan USA offers its carbide drills in both an uncoated option, and AlTiN coating. Traditionally, uncoated tools are general purpose workhorses in a wide variety of materials both ferrous and non-ferrous. AlTiN or Aluminum Titanium Nitride is an enhanced coating specifically made for ferrous materials that extends tool life and performance across a wide range of steels and their alloys.
For more information on Titan USA Drills, and to view its full selection, click here.
Unlike most CNC cutting tools, Thread Forming Taps, otherwise known as Form Taps, Forming Taps, or Roll Taps, work by molding the workpiece rather than cutting it. Because of this, Form Taps do not contain any flutes, as there is no cutting action taking place, nor are there any chips to evacuate. Below are 8 unique facts of Thread Forming Taps (and some may surprise you).
1. Chips Aren’t Formed
When using a Form Tap, chips are not formed, nor is any part material evacuated (Yes, you read that right). With thread forming, the tool is void of any flutes, as chip evacuation is not a concern. Form Taps quite literally mold the workpiece, rather than cut it, to produce threads. Material is displaced within a hole to make way for the threads being formed.
2. Cutting Oils Allow for Reduced Friction & Heat Generation
Did you know that Thread Forming Taps require good lubrication? But why is that the case if chips are not being evacuated, and how does lubrication enter the part with such a limited area between the tool and the perimeter of the hole being threaded? Despite the fact that chips aren’t being formed or evacuated, cutting oils aid the Form Tap as it interacts with the part material, and reduces friction and heat generation. Lube vent grooves are narrow channels engineered into the side of Forming Taps that are designed to provide just enough room for lubricant to make its way into – and out of – a part.
3. Only Certain Materials Are Recommended for Thread Forming
Not all materials are well suited for Thread Forming Taps. In fact, attempting to use a tap in the wrong material can result in significant part and tool damage. The best materials for this unique type of operation include aluminum, brass, copper, 300 stainless steel, and leaded steel. In other words, any material that leaves a stringy chip is a good candidate for cold forming threads. Materials that leave a powdery chip, such as cast iron, are likely too brittle, resulting in ineffective, porous threads.
4. Threads Produced Are Stronger Than Conventional Tapping Threads
Thread forming produces much stronger threads than conventional tapping methods, due to the displacements of the grain of the metal in the workpiece. Further, cutting taps produce chips, which may interfere with the tapping process.
5. Chip Evacuation is Never a Concern With Thread Forming
In conventional tapping applications, as with most machining applications, chip evacuation is a concern. This is especially true in blind holes, or holes with a bottom, as chips created at the very bottom of the hole oftentimes have a long distance to travel before being efficiently evacuated. With form taps, however, chip removal is never a concern.
6. Form Taps Offer Extended Tool Life
Thread Forming Taps are incredibly efficient, as their tool life is substantial (Up to 20x longer than cutting taps), as they have no cutting edges to dull. Further, Thread Forms can be run at faster speeds (Up to 2x faster than Cutting Taps).
Pro Tip: To prolong tool life even further, opt for a coated tool. Titan USA Form Taps, for example, are fully stocked in both uncoated and TiN coated styles.
7. A Simple Formula Will Help You Find the Right Drill Size
When selecting a Tap, you must be familiar with the following formula, which will help a machinist determine the proper drill size needed for creating the starter hole, before a Thread Forming Tap is used to finish the application:
Drill Size = Major Diameter – [(0.0068 x desired % of thread) / Threads Per Inch] Drill Size (mm) = Major Diameter – [(0.0068 x desired % of thread x pitch (mm)]
8. Thread Forming Taps Need a Larger Hole Size
Thread Form Taps require a larger pre-tap hole size than a cutting tap. This is because these tools impact the sides of the hole consistently during the thread forming process. If the pre-tap hole size is too small, the tool would have to work too hard to perform its job, resulting in excessive tool wear, torque, and possible breakage.
As an example, a ¼-20 cut tap requires a #7 drill size for the starter hole, whereas a ¼-20 roll tap requires a #1 drill size for 65% thread.
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.”
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.
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.
Just looking at a thread milling 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.
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.
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.
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.
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.
https://www.harveyperformance.com/wp-content/uploads/2018/03/Feature-Image-Stop-Deburring-by-Hand-IMG-1.jpg5251400Harvey Performance Companyhttp://www.harveyperformance.com/wp-content/uploads/2018/08/Logo_HarveyPerformanceCompany-4.pngHarvey Performance Company2018-03-13 16:26:182022-06-09 11:28:10Why You Should Stop Deburring by Hand
Coolant in purpose is widely understood – it’s used to temper high temperatures common during machining, and aid in chip evacuation. However, there are several types and styles, each with its own benefits and drawbacks. Knowing which cnc coolant – or if any – is appropriate for your job can help to boost your shop’s profitability, capability, and overall machining performance.
Coolant or Lubricant Purpose
Coolant and lubricant are terms used interchangeably, though not all coolants are lubricants. Compressed air, for example, has no lubricating purpose but works only as a cooling option. Direct coolants – those which make physical contact with a part – can be compressed air, water, oil, synthetics, or semi-synthetics. When directed to the cutting action of a tool, these can help to fend off high temperatures that could lead to melting, warping, discoloration, or tool failure. Additionally, coolant can help evacuate chips from a part, preventing chip recutting and aiding in part finish.
Coolant can be expensive, however, and wasteful if not necessary. Understanding the amount of coolant needed for your job can help your shop’s efficiency.
CNC coolant is delivered in several different forms – both in properties and pressure. The most common forms include air, mist, flood coolant, high pressure, and Minimum Quantity Lubricant (MQL). Choosing the wrong pressure can lead to part or tool damage, whereas choosing the wrong amount can lead to exhausted shop resources.
Air: Cools and clears chips, but has no lubricity purpose. Air coolant does not cool as efficiently as water or oil-based coolants. For more sensitive materials, air coolant is often preferred over types that come in direct contact with the part. This is true with many plastics, where thermal shock – or rapid expansion and contraction of a part – can occur if direct coolant is applied.
Mist: This type of low pressure coolant is sufficient for instances where chip evacuation and heat are not major concerns. Because the pressure applied is not great in a mist, the part and tool do not undergo additional stresses.
Flood: This low pressure method creates lubricity and flushes chips from a part to avoid chip recutting, a common and tool damaging occurrence.
High Pressure: Similar to flood coolant, but delivered in greater than 1,000 psi. This is a great option for chip removal and evacuation, as it blasts the chips away from the part. While this method will effectively cool a part immediately, the pressure can be high enough to break miniature diameter tooling. This method is used often in deep pocket or drilling operations, and can be delivered via coolant through tooling, or coolant grooves built into the tool itself. Harvey Tool offers Coolant Through Drills, while Titan USA proudly offers Coolant-Fed ThreadMills
Minimum Quantity Lubricant (MQL): Every machine shop focuses on how to gain a competitive advantage – to spend less, make more, and boost shop efficiency. That’s why many shops are opting for MQL, along with its obvious environmental benefits. Using only the necessary amount of coolant will dramatically reduce costs and wasted material. This type of lubricant is applied as an aerosol, or an extremely fine mist, to provide just enough coolant to perform a given operation effectively.
To see all of these coolant styles in action, check out the video below from our partners at CimQuest.
CNC coolant is all-too-often overlooked as a major component of a machining operation. The type of coolant or lubricant, and the pressure at which it’s applied, is vital to both machining success and optimum shop efficiency. Coolant can be applied as compressed air, mist, in a flooding property, or as high pressure. Certain machines also are MQL able, meaning they can effectively restrict the amount of coolant being applied to the very amount necessary to avoid being wasteful.
https://www.harveyperformance.com/wp-content/uploads/2017/12/Feature-Image-Coolant-for-CNC-Machining-IMG.jpg5251400Harvey Performance Companyhttp://www.harveyperformance.com/wp-content/uploads/2018/08/Logo_HarveyPerformanceCompany-4.pngHarvey Performance Company2017-12-05 15:09:342022-04-20 16:52:22What You Need to Know About Coolant for CNC Machining