PCD VS. CVD
There are pros and cons to both PCD and CVD cutting tools.
We have experts who can answer your questions about PCD & CVD diamond cutting tools.
At General Cutting Tools, specials and modifications refer to two unique categories of tooling solutions customized to meet specific manufacturing requirements.
Specials:
Tools entirely custom-designed and built specifically to solve unique manufacturing challenges or requirements not achievable by standard off-the-shelf tools.
Modifications:
Standard, off-the-shelf cutting tools that are adjusted or altered slightly to meet specific operational requirements.
Characteristics:
- Completely unique geometry and dimensions.
- Custom coatings, tool materials, or cutting-edge shapes.
- Often created for specific production processes, unusual materials, or specialized manufacturing operations.
- Usually involves detailed engineering and manufacturing processes, resulting in higher costs and longer production lead times.
Characteristics:
- Minor adjustments such as regrinding, shortening overall length, changing cutting angles, reducing diameters, or applying specialized coatings.
- Cost-effective and quicker turnaround since the base tooling already exists.
- Used when standard tooling is almost suitable but requires slight alterations to optimize performance or fit.
Example: A specially ground tool designed to create a complex form, shape or profile in machining components.
Example: Regrinding or reshaping a standard drill bit to alter tip geometry or diameter for better hole accuracy or adjusting the shank size of a milling cutter to fit a particular machine.
Specials Vs. Modifications for General Manufacturing Cutting Tools:
| Feature | Specials | Modifications |
|---|---|---|
| Design Approach | Fully custom-designed | Alterations to existing standard tooling |
| Extent of Customization | Complete, extensive customization | Minor refinements or adjustments |
| Cost Impact | Higher initial investment | Lower, cost-effective modifications |
| Lead Time | Longer, involving custom production | Shorter, quick turnaround |
| Typical Usage | Highly specialized manufacturing tasks | General production adjustments |
Selecting between specials or modifications is based on how closely a standard tool aligns with the application, urgency, and cost considerations.
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For composites, diamond cutting tools can be divided into two types: PCD tools, which are built from PCD segments of a specific size and shape, and CVD diamond coated tools, which are built entirely in a grinding operation and then coated with CVD diamond.
PCD
Poly-Crystalline Diamond is a synthetic diamond, unlike single crystal diamond, produced by sintering together many (Poly) diamond particles with a metal binder (usually Cobalt) at high temperatures and pressures. 90%-95% of the particles are diamond, and the rest are cobalt.
CVD
Chemical Vapor Deposition – A layer thickness of 6 to 16 microns of a meter is applied to a Tungsten carbide substrate through Chemical Vapor Deposition. It must contain a low cobalt content, such as 6%, and have a specific surface treatment. To create sufficient adhesion between the diamond coating and the substrate, the treatment reduces the cobalt content in the outer layer.
CVD & PCD Comparison:
| PCD | CVD Diamond coating | |
| Hardness | PCD is a composite diamond composed of 90-95% diamond powder + cobalt binder, which has a lower hardness than CVD. Hardness of around 6000 Vickers. | Since CVD is 99% pure diamond, it has the highest hardness. Hardness of around 8500 Vickers. |
| Wear resistance | PCD contains cobalt, so the edge wears faster until a certain edge radius is reached and remains constant for a long time. | Due to CVD’s pure diamond coating, edge radius is maintained sharper for a longer period of time. Since the material beneath the coating is tungsten carbide, when the coating wears off, edge sharpness deteriorates much faster. |
| Durability | The cobalt metal binder in the PCD material adds to the strength of the material, as compared to the CVD diamond. Therefore it is likely to have better resistance to chipping in milling operations and in unstable machining conditions. | The almost pure diamond layer has lower elasticity and strength, therefore would be more likely to fracture and delaminate than the PCD. |
| Construction | The geometry of PCD tools in the form of wafer segments is limited by the shape of the segment. PCDs with full nibs, however, do not have design limitations. | The geometry design of CVD tools is not limited due to the fact that they are shaped first in a grinding operation. |
Application
Diamond is an ideal material for manufacturing cutting tools due to its extreme hardness, wear resistance, and thermal conductivity. All non ferrous materials can be machined with PCD tools, including chipboards, HDF, laminated boards, materials used by the automotive industry to make aluminium components, and lightweight materials, such as carbon fiber reinforced plastics (CFRP), metal matrix composites (MMC) and stacks for aircraft construction.
Unlike milling, drilling has constant contact with the material, so the cutting edge is less likely to chip or fracture. As a result, CVD diamond drills minimize delamination at the hole exit by combining hardness and sharpness. In highly engineered parts, such as aerospace, drilling composites is a major concern. CVD drills outperform PCD drills when delamination is the failure criterion. If hole diameter is the failure criteria, PCD drills will “survive” longer than CVD drills. This is because CVD diamond is a coating. Edge wear accelerates rapidly when it delaminates from tungsten carbide. PCDs, on the other hand, are solid diamonds. Wear develops almost continuously. Stack materials like CFRP/Al, where the exit hole is in aluminum, may also benefit from a PCD drill. The best choice is PCD, since it will last longer and can also be reconditioned a few times, since delamination is not an issue. Unlike wafer drills whose geometry is determined by PCD segments, CVD diamond drills would also provide design flexibility. A Fullnib PCD drill, however, has no geometry limitation and design flexibility is the same as a CVD diamond drill as long as PCD nib height (which is limited) does not create additional limitations.
PCD or CVD in Countersinking operations:
The countersink body is made from steel due to the thread connection, despite countersinking being a manual operation. Since CVD diamond cannot be coated on steel, most composite countersinks are PCD. The steel body of the countersink is brazed with PCD segments. Due to the difficulty of grinding the thread on the tungsten carbide body, coating full carbide countersinks is rarely seen.
There are pros and cons to both PCD and CVD cutting tools. Neither of them can fully replace the other. Other factors such as tool cost, reconditioning, tool diameter limitations, and more were not discussed in this article. We will discuss some of these factors in the following articles. We offer PCD and CVD diamond Drills, End Mills, Routers and countersinks for all your composites applications at General Cutting Tools.
Order Amana Tool PCD Cutting Tools
Diamond Tipped (PCD) CNC Ball Nose Router Bits
DRB-432 CNC Polycrystalline Diamond (PCD) Ball Nose 1/8 Radius x 1/4 Dia x 3/8 x 1/4 Shank x 2-1/2 Inch Long x 2 Flute Router Bit
DRB-433 CNC Polycrystalline Diamond (PCD) Ball Nose 3/16 Radius x 3/8 Dia x 1/2 x 3/8 Shank x 3 Inch Long x 2 Flute Router Bit
DRB-435 CNC Polycrystalline Diamond (PCD) Ball Nose 3/8 Radius x 3/4 Dia x 3/4 x 1/2 Shank x 3 Inch Long x 2 Flute Router Bit
DRB-434 CNC Polycrystalline Diamond (PCD) Ball Nose 1/4 Radius x 1/2 Dia x 1/2 x 1/2 Shank x 3 Inch Long x 2 Flute Router Bit
Diamond Tipped (PCD) CNC Spoilboard Router Bits
DRB-440 Polycrystalline Diamond (PCD) Tipped CNC Spoilboard Surfacing, Rabbeting, Flycutter, Slab Leveler & Surface Planer 1-1/2 Dia x 1/2 Inch x 1/2 Shank
DRB-442 Polycrystalline Diamond (PCD) Tipped CNC Spoilboard Surfacing, Rabbeting, Flycutter, Slab Leveler & Surface Planer 3" Dia x 1/16 Radius x 10mm x 1/2 Shank
DRB-444 Polycrystalline Diamond (PCD) Tipped CNC Spoilboard Surfacing, Rabbeting, Flycutter, Slab Leveler & Surface Planer 4″ Dia x 1/16 Radius x 10mm x 1/2 Shank
Diamond Tipped (PCD) CNC V-Engraving/Chamfering Router Bits
DRB-416 CNC Polycrystalline Diamond (PCD) 60 Degree Engraving, V-Grooving and Chamfering Router Bit 1/4 Dia x 1/8 x 1/4 Shank
DRB-418 CNC Polycrystalline Diamond (PCD) 90 Degree Engraving, V-Grooving and Chamfering Router Bit 1/2 Dia x 1/4 x 1/4 Shank
DRB-417 CNC Polycrystalline Diamond (PCD) 90 Degree Engraving, V-Grooving and Chamfering Router Bit 1 Dia x 1/2 x 1/2 Shank
DRB-419 CNC Polycrystalline Diamond (PCD) 120 Degree Engraving, V-Grooving and Chamfering Router Bit 1-1/2 Dia x .43 Inch x 1/2 Shank
Diamond Tipped (PCD) CNC Up/Down Shear Right Hand Rotation Router Bits
DRB-200 CNC Polycrystalline Diamond (PCD) Tipped Compression Up/Down Shear R/H Direction 1+1 Flute x 1/2 Dia x 1 Inch x 1/2 Shank Router Bit
DRB-208 CNC Polycrystalline Diamond (PCD) Tipped Compression Up/Down Shear R/H Direction 1+1 Flute x 1/2 Dia x 1-3/8 x 1/2 Inch Shank Router Bit
DRB-212 CNC Polycrystalline Diamond (PCD) Tipped Compression Up/Down Shear R/H Direction 1+1 Flute x 5/8 Dia x 1 Inch x 1/2 Shank Router Bit
DRB-224 CNC Polycrystalline Diamond (PCD) Tipped Compression Up/Down Shear R/H Direction 1+1 Flute x 3/4 Dia x 1-3/8 x 3/4 Shank Router Bit
DRB-216 CNC Polycrystalline Diamond (PCD) Tipped Compression Up/Down Shear R/H Direction 1+1 Flute x 5/8 Dia x 1-5/8 x 5/8 Shank Router Bit
DRB-192 CNC Polycrystalline Diamond (PCD) Tipped Compression Up/Down Shear R/H Direction 1+1 Flute x 3/8 Dia x 1-1/4 Inch x 3/8 Shank Router Bit
DRB-240 CNC Polycrystalline Diamond (PCD) Tipped Compression Up/Down Shear R/H Direction 2+2 Flute x 1/2 Dia x 3/4 x 1/2 Shank Router Bit
DRB-242 CNC Polycrystalline Diamond (PCD) Tipped Compression Up/Down Shear R/H Direction 2+2 Flute x 1/2 Dia x 7/8 x 1/2 Shank Router Bit
DRB-244 CNC Polycrystalline Diamond (PCD) Tipped Compression Up/Down Shear R/H Direction 2+2 Flute x 1/2 Dia x 1-3/8 x 1/2 Shank Router Bit
DRB-250 CNC Polycrystalline Diamond (PCD) Tipped Compression Up/Down Shear R/H Direction 3+3 Flute x 1/2 Dia x 1-3/8 x 1/2 Shank Router Bit
DRB-228 CNC Polycrystalline Diamond (PCD) Tipped Compression Up/Down Shear R/H Direction 1+1 Flute x 3/4 Dia x 1-5/8 x 3/4 Shank Router Bit
DRB-260 CNC Polycrystalline Diamond (PCD) Tipped Compression Up/Down Shear 3+1 Flute x 1/2 Dia x 1 x 1/2 Shank Router Bit
DRB-190 CNC Polycrystalline Diamond (PCD) Tipped Compression Up/Down Shear R/H Direction 1+1 Flute x 1/4 Dia x 3/4 x 1/4 Inch Shank Router Bit
Diamond Tipped (PCD) Straight Plunge Router Bits
DRB-420 Polycrystalline Diamond (PCD) Tipped Double Flute 1/4 Dia x 3/4 Inch x 1/4 Shank Straight Plunge
DRB-424 Polycrystalline Diamond (PCD) Tipped Double Flute 1/2 Dia x 3/4 Inch x 1/2 Shank Straight Plunge
DRB-425 Polycrystalline Diamond (PCD) Tipped Double Flute 1/2 Dia x 1 Inch x 1/2 Shank Straight Plunge
Diamond Tipped (PCD) Single Flute Down-Shear Straight Plunge Router Bits
DRB-421 Straight Plunge Down-Shear Polycrystalline Diamond (PCD) Tipped 1/4 Dia x 12.32mm (1/2) x 1/4 Shank Single Flute Router Bit
DRB-422 Straight Plunge Down-Shear Polycrystalline Diamond (PCD) Tipped 3/8 Dia x 15.35mm (5/8) x 3/8 Shank Single Flute Router Bit
DRB-423 Straight Plunge Down-Shear Polycrystalline Diamond (PCD) Tipped 1/2 Dia x 15.00mm (5/8) x 1/2 Shank 2 Flute Router Bit
Diamond Tipped (PCD) Double Edge Folding 'V' Groove Router Bits
DRB-450 Polycrystalline Diamond (PCD) Tipped Double Edge Folding V-Groove 90 Deg x 0.090 Inch Tip Width x 1/2 Dia x 13/64 x 1/4 Inch Shank
Diamond Tipped (PCD) CNC T-Slot Router Bits
DRB-300-RH CNC Polycrystalline Diamond (PCD) Tipped T-Slot 1-3/8 Dia x 1/4 x 1/2 Inch Shank Router Bit 2+1 Cutters