1. What is the difference between CVD diamond and Amorphous diamond?
2. I heard that CVD Diamond tools only work with high speed machining.
3. Can I use Diamond Tools on Hardened Steel?
4. Can I resharpen a diamond coated tool and have it recoated?
5. Do You Take Custom Orders?
6. How Long will a Diamond Coated tool last?
7. How do you grow diamond?
8. I have heard a lot about diamond peeling off of diamond coated tools, resulting in unrepeatable life. What does CVD Diamond do to prevent this problem?
9. Are Diamond Coated tools fragile?
10. Are Diamond Coated Tools Expensive?



1.  What is the difference between CVD diamond and Amorphous diamond?
The process of Chemical Vapor Deposition of Diamond results in a pure diamond film that is polycrystalline. As such it has the properties of pure diamond, including:

Highest hardness of any material
Strongest known material
Highest known value of thermal conductivity
Very resistant to chemical corrosion
Frictional properties similar to Teflon

Amorphous diamond also called Diamond Like Carbon (DLC) is not a crystalline structure and is not diamond. Amorphous diamond films typically last about 10% to 15% the life of a CVD diamond coated tool.

2. I heard that CVD Diamond tools only work with high speed machining.

In general terms the higher the speed the higher the multiple of life over a tungsten carbide tool, however at relatively low speeds, diamond coated tools will pay for themselves. We have conducted extensive tests at relatively low speeds to verify this. At 245 SFM we have consistently achieved about 12 times the life of a bare carbide tool in POCO Graphite. This corresponds to running a 1/8" tool at 7,500 RPM or a 1/2" tool at less than 2000 rpm. By most standards this would not be considered "high speed". For further information on Feeds and Speeds see Machining Graphite with CVD Diamond.

3. Can I use Diamond Tools on Hardened Steel?
Diamond is composed of carbon atoms. Some materials, when heated will absorb carbon to form carbides in the workpiece. Unfortunately Iron is one such material. When Machining ferrous materials, friction provides the heat necessary to cause the right conditions for the carbon from the diamond to diffuse into the iron, causing chemical wear of the film. This results in premature wear and the diamond cannot pay for itself.


4. Can I resharpen a diamond coated tool and have it recoated?
Since the film we produce is pure diamond, resharpening the tool with a diamond wheel will take a long time. In addition the process we use to prepare the tool for diamond growth alters the chemistry of the tool at the surface. Since this chemistry needs to be very closely managed, we cannot guarantee the results of a tool that has been recoated.


5. Do You Take Custom Orders?
Yes, feel free to discuss your need for special tools with us. Tools can be made as specials, or if there is enough demand for the tools we will consider making it a stock item.


6. How Long will a Diamond Coated tool last?
Like any other tool, the life of a diamond-coated tool will vary depending on the material being cut, the feeds and speeds chosen and the geometry of the part.

As a rule, in graphite our diamond-coated tools will last 10-20 times as long as a bare tungsten carbide tool. In some cases it could last even longer than that! This will allow pretty well any job to be done completely with 1 tool with no change due to wear, no interruption, and no recalibration. This allows lights out operation.

In composite materials it is not unusual to get substantially longer life. Our customers have reported up to 70 times the life of a bare carbide tool in High density Fiberglass, Carbon Fiber and G10-FR4.

We are gaining experience in other materials on a daily basis. If you have a specific material you are interested in, please feel free to contact us.


7. How do you grow diamond?
CVD Diamond Corporation uses a process called Chemical Vapor Deposition to remove the carbon atoms from methane gas and to deposit them directly onto the tool as diamond. The process we use results in a continuous film which is highly homogeneous, accounting for consistent lifetime of our tools.


8. I have heard a lot about diamond peeling off of diamond coated tools, resulting in unrepeatable life. What does CVD Diamond do to prevent this problem?
This has been a serious problem with diamond coated tools. In the late 1990's interface chemistry was identified as the important issue in adhesion of the diamond film. CVD Diamond Corporation has carefully selected the carbide chemistry it uses for substrates. It uses surface preparation technique and reactor conditions that very carefully manage the interface chemistry, resulting in a very adherent diamond film. When our diamond coated tools are worn out examination under a microscope reveals that the diamond has worn all the way through to the carbide rather than chipping or peeling off.

9. Are Diamond Coated tools fragile?
While diamond is extremely hard and extremely strong, one characteristic of the material is that it is brittle. Brittle materials tend to crack as a result of impact. CVD Diamond Corporation minimizes this effect by keeping the film as thin as possible while providing the life required in a given application, however it is very easy to chip a diamond coated tool. For this reason we have chosen to use packaging which protects the tool very well. We recommend careful handling of our diamond-coated tools, and the use of the original package between uses of the tools.


10. Are Diamond Coated Tools Expensive?
The use of our diamond-coated tools will actually reduce the cost of tooling by as much as 85%. This is on tooling cost alone. If your operation is such that downtime of the machine is costly or interruptions due to tool wear are costly, the savings can be even higher.

Since the operating range for diamond coated tools is very broad they offer the opportunity for significant increases in productivity. As an example a 1/2" end mill can be run anywhere from 1500 rpm to speeds up to 30,000rpm, therefore machining times can be cut in half.

The initial outlay for a diamond coated tool is about 5 times as high as a good quality carbide tool, but with the opportunity for 10-20 times the life and other considerations mentioned above allow the cost justification to be easily made.

A recent case study with an automotive customer machining high-density fiberglass demonstrates savings.

The customer was able to machine 15 parts with a 1/4 end mill they were paying $15.00 for. With a high rate of production this was an unacceptable situation due to the cost of end mills and the large number of mills required to machine an average of one part per minute. Downtime to constantly be changing tools was also a consideration, as was the cost of having to set up so many tools.

Our diamond coated end mill at $150.00, runs for over 750 parts, saves the customer over $600.00 for every tool run, requires 50 times less tool changes and 50 times less tool set ups.

The yearly savings in this case are well in excess of $600,000.