Posts

Shining a Light on Diamond End Mills

Diamond tooling and diamond-coated end mills are a great option when machining highly abrasive materials, as the coating properties help to significantly increase tool life relative to uncoated carbide tools. Diamond tools and diamond-like coated tools are only recommended for non-ferrous applications, including highly abrasive materials ranging from graphite to green ceramics, as they have a tendency to break down in the presence of extreme heat.

Understanding the Properties of Diamond Coatings

To ensure proper diamond tooling selection, it’s critical to understand the unique properties and makeup of the coatings, as there are often several diamond coating variations to choose from. Harvey Tool, for example, stocks Amorphous Diamond, CVD Diamond, and PCD Diamond End Mills for customers looking to achieve significantly greater tool life when working in non-ferrous applications.

Diamond, the hardest known material on earth, obtains its strength from the structure of carbon molecules. Graphite, a relatively brittle material, can have the same chemical formula as diamond, but is a completely different material; while Graphite has a sp2 bonded hexagonal structure, diamond has a sp3 bonded cubic structure. The cubic structure is harder than the hexagonal structure as more single bonds can be formed to interweave the carbon into a stronger network of molecules.

diamond tool coatings

Amorphous Diamond Coating

Amorphous Diamond is transferred onto carbide tools through a process called physical vapor deposition (PVD). This process spreads a mono-layer of DLC coating about 0.5 – 2.5 microns thick onto any given tool by evaporating a source material and allowing it to condense onto that tool over the course of a few hours.

amorphous diamond coating

Chemical Vapor Deposition (CVD)

Chemical Vapor Deposition (CVD) is a coating process used to grow multiple layers of polycrystalline diamond onto carbide tooling. This procedure takes much longer than the standard PVD coating method. During the coating process, hydrogen molecules are dissociated from the carbon molecules deposited onto the tool, leaving a diamond matrix under the right temperature and pressure conditions. Under the wrong conditions, the tool may be simply coated in graphite. 6% cobalt carbide blanks allow for the best adhesion of diamond and a substrate. CVD diamond coated end mills have a typical thickness of coating that is between 8 and 10 microns thick.

CVD Diamond Coating

Polycrystalline Diamond (PCD)

Polycrystalline Diamond (PCD) is a synthetic diamond, meaning it is grown in a lab and contains mostly cubic structures. Diamond hardness ranges from about 80 GPa up to about 98 GPa. PCD end mills have the same diamond structure as CVD diamond tools but the binding technique is different. The diamond starts in a powdery form that is sintered onto a carbide plate using cobalt as a solvent metal substrate. This is done at an extreme temperature and pressure as the cobalt infiltrates the powder, causing the grains to grow together. This effectively creates a thick diamond wafer, between 010” and .030” in width, with a carbide base. This carbide base is then brazed onto the head an end mill and sharpened.

PCD Diamond CoatingHow Diamond Coatings Differ

Coating Hardness & Thickness

Polycrystalline tools (CVD or sintered) have a much higher hardness, thickness, and max working temperature than Amorphous Diamond oated tools. As mentioned previously, a PCD tool consists of a diamond wafer brazed to a carbide body while a CVD tool is a carbide end mill with a relatively thick layer of polycrystalline diamond grown into it. This grown layer causes the CVD tools to have a rounded cutting edge compared to PCD and Amorphous Diamond coated tools. PCD tools have the thickest diamond layer that is ground to a sharp edge for maximum performance and tool life. The difference between PCD tools and CVD coated tools lies in the thickness of this coat and the sharpness of the cutting edge. Amorphous Diamond tools maintain a sharper edge than CVD coated tools because of their thin coating.

Flute Styles

Harvey Tool’s line of PCD end mills are all straight fluted, CVD coated tools are all helically fluted, and Amorphous Diamond tools are offered in a variety of options. The contrast between straight fluted and helically fluted can be seen in the images below, PCD (top) and CVD (bottom). Electrical discharge machining, grinding or erosion are used cut the PCD wafer to the specifications. The size of this wafer limits the range of diameters that can be achieved during manufacturing. In most situations a helically fluted tool would be preferred over a straight fluted tool but with true diamond tooling that is not the case. The materials that PCD tools and CVD coated tools are typically used to cut produce a powdery chip that does not require the same evacuation that a metallic or plastic chip necessitates.

PCD Diamond end mill

PCD Ball End Mill

CVD Diamond end mill

CVD Ball End Mill

Proper Uses

CVD tools are ideally suited for abrasive material not requiring a sharp cutting edge – typically materials that produce a powdery chip such as composites and graphite. Amorphous Diamond tools have a broad range of non-ferrous applications spanning from carbon fiber to precious metals but ceramics are typically outside their range as they can be too abrasive and wear away the coating. PCD tools overlap their CVD and DLC coated counterparts as they can be used for any non-ferrous abrasive material.

Cut to the Point

Harvey Tool carries physical vapor deposition diamond-like carbon coated tools, chemical vapor deposition diamond tools and polycrystalline diamond tools. PCD tools are composed of the thickest diamond wafer brazed onto a carbide shank and are ground to a sharp edge. CVD coated tools have the diamond grown into a carbide end mill. Amorphous Diamond coated tools have the DLC coated onto them through the PVD process. For more information on the diamond coating best suited for your operation, contact a Harvey Tool Tech Team Member for immediate help.

Multi-Functional Tools Every Shop Should Have

If there is one thing that all machinists and shop managers can agree on, it’s that time is money. Tool and material costs, employee wages, and keeping the lights on all add up, but most would agree that saving time is one of the best ways to make a shop more efficient.

Tool changes mid-job quickly add up when it comes to cycle times (not to mention tool costs), so using a tool capable of multiple operations whenever possible is an excellent first step. The following multi-functional tools are designed to save time and money at the spindle.

Drill/End Mills

drill mills

One look at Drill/End Mills or “Drill Mills” and it’s obvious that these tools are capable of more than a standard end mill. Two of the intended operations are right in the name (drilling and milling). Besides the obvious, though, drill mills are intended for grooving, spotting, and chamfering, bringing the total to five separate operations.

drill mill operations

Considering the amount of tools normally required to perform all of these common operations, keeping a few drill mills in your tool crib ensures you’re always ready to tackle them, not to mention the potential extra spots in your tool magazine.

Undercutting End Mills

undercutting end mills

Undercutting End Mills, also known as lollipop cutters or spherical ball end mills are surprisingly “well-rounded” tools. Besides milling an undercut feature on a part, which is typically very difficult with a standard end mill, these tools are capable of a few other operations.

undercutting end mill operations

Using an undercutting end mill to deburr in your machine is an excellent way to save time and effort. Some slotting and contouring operations, especially when 5-axis milling, are made far easier with an undercutting end mill, and in some situations, clearance challenges make them necessary.

Double Angle Shank Cutters

double angle shank cutters

Often referred to the “Swiss Army Knife of Machining” due to their versatility, Double Angle Shank Cutters are 6-in1 tools worth keeping on hand in any machine shop. Since these tools cut on all sides of their head, they are useful in a variety of situations.

multi-functional tools

With the ability to thread mill and countersink, Double Angle Shank cutters are perfect for holemaking operations. On top of that, their clearance advantage over standard end mills makes them extremely well suited to a variety of finishing operations in difficult to reach places.

Flat Bottom Tools

flat bottom tools

Flat Bottom Drills and Flat Bottom Counterbores are better suited to holemaking, but they are capable of a large variety of operations. They belong in a category together since their flat bottom geometry is what sets them apart from other tools in the same category. Flat bottom geometry keeps the tool from walking on irregular or angle surfaces and help to correct, straighten, or flatten features created by non-flat bottom tools.

Flat bottom drills are designed for the following operations:

multi-functional tools

While similar in some aspects, flat bottom counterbores are particularly well-suited for these uses:

flat bottom tools

Adjustable Chamfer Cutters

adjustable chamfer cutters

As discussed in a previous post, chamfer mills are capable of more than just chamfering – they are also well-suited for beveling, deburring, spotting, and countersinking. However, these adjustable chamfer cutters aren’t limited to a single angle per side – with a quick adjustment to the carbide insert you can mill any angle from 10° to 80°.

chamfer cutter inserts

When you account for the replaceable insert and the range of angles, this tool has a very high potential for time and tool cost savings.

Tools that are capable of a variety of operations are useful to just about any machine shop. Keeping your tool crib stocked with some or all of these multi-functional tools greatly increases your shop’s flexibility and decreases the chances of being unprepared for a job.

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.

Undercutting End Mills: Well-Rounded Tools That Offer Maximum Versatility

Undercutting end mills, also known as lollipop cutters or spherical ball end mills, are a common choice for machining undercuts. An undercut is a common part feature characterized by one part of a workpiece “hanging” over another. Undercuts are typically difficult, or even impossible, to machine with a standard end mill, especially on 3-axis machines. In many cases, a specialty tool is needed to tackle this feature. Although they are frequently associated with a singular use, undercutting end mills are actually very versatile tools that are worth keeping on hand for a variety of operations.

Undercutting

undercutting machining

Unsurprisingly, undercutting end mills are very well suited to undercutting operations. Creating an undercut on a part can be tricky and time consuming, especially when forced to rotate the workpiece. Fortunately, this can be greatly simplified with an undercutting end mill.

Exactly what tool to use depends on the geometry of the feature and the part. Undercutting end mills are available with a range of wrap angles like 220°, 270°, and 300°. Greater wrap angles are the result of a thinner neck and create a more spherical cutting end. This style offers more clearance at the cost of rigidity. Likewise, undercutting end mills with lower wrap angles sacrifice clearance for greater rigidity.

Deburring & Edgebreaking

deburring

Since undercuts have a wrap angle that is greater than 180°, they are very well-suited to deburring or edgebreaking anywhere on your workpiece, including the underside. Deburring your parts by hand can be inefficient for your shop – using an undercutting end mill instead will save you time and money. Edgebreaking operations are often a critical final step to create a part that looks and feels like a finished product and that is safe to handle.

All undercutting end mills can be used to deburr and edgebreak, which makes them a useful tool to have on hand in any shop. Some manufacturers also offer specialized deburring undercutting end mills that are designed with a right and left hand flute orientation, giving them “teeth” that make them particularly useful for deburring complex shapes. Using a deburring undercutting end mill in a 5-axis machine often makes it possible to deburr or edgebreak an entire workpiece in one shot.

Slotting

slotting

Most machinists might not think of undercutting end mills for slotting, but they are fully capable of this operation. An equivalent slot can be machined with a regular ball end mill, but doing so might not be feasible due to clearance issues – an undercutting end mill has a reduced neck, unlike a standard ball end mill. Additionally, using an undercutter to slot can save time switching to an equivalent ball end mill.

Since only 180° of the cutting end can be used to slot, undercutting end mills with lower wrap angles and thicker necks are best suited to slotting. However, high helix undercutting end mills may be ideal if improved finish and increased chip removal are important to the operation.

Contouring & Profiling

contouring

With their wrap angle and increased clearance, undercutting end mills are very useful for both simple and complicated contouring and profiling operations. Their versatility means that it is sometimes possible to accomplish the entire operation with a single tool, rather than several, especially when 5-axis milling.

Reduced shank undercutting end mills offer the most versatility in complex contouring and profiling operations. The ability to chuck these tools at any depth means that they are capable of maximum clearance.

Choosing An Undercutting End Mill

While most undercutting end mills are conceptually similar, there are a few key differences that must be considered when picking the right tool for your job. Harvey Tool offers the following undercutting end mill styles as stock standard tools.

undercutting end mills