PCD drills are specified for CFRP and other aerospace-grade composite laminates because a hard, sharp polycrystalline diamond edge cuts fibres cleanly instead of pulling them out of the laminate. That is what limits delamination, fuzzing and chipping at the hole entry and exit. Choosing between a PCD drill and a coated drill starts with the material system, the nominal diameters and the tolerance the holes have to hold.
A composite laminate is built from layers of fibre held in a matrix. As the drill approaches breakthrough, the remaining layers lose support from below, so the cutting edge pushes fibres ahead of it rather than severing them. The result is delamination at the exit side, fuzzing around the hole wall and chipping at the entry. A worn or rounded edge makes all three worse because it rubs instead of cutting.
This is why hole quality in CFRP and SMC laminates is treated as a cutting-edge problem first. The edge has to shear the fibre bundle cleanly at the point where the laminate is least supported, and it has to stay sharp against abrasive fibres and filler particles.
| Hole defect | Where it appears | What drives it |
| Delamination | Exit side, at breakthrough | Unsupported outer layers pushed apart by the drill point |
| Fuzzing | Hole wall and rim | Fibres pulled out instead of sheared by a rounded edge |
| Chipping | Entry side | Impact as the edge first engages the surface ply |
| Flanging | Exit rim | Fibre bundles bent over rather than cut through |
Requests for aerospace composite drilling often ask for both routes in the same line: PCD or coated drills. Among CFRP cutting tools, these are the two options most frequently compared. They are not interchangeable labels, and the right choice depends on the laminate system, the hole quality requirement and the diameter range, not on a single headline property.
| Selection factor | What to confirm | Why it changes the choice |
| Material system | CFR, SMC or another aerospace-grade laminate, including fibre and filler type | Abrasiveness governs how quickly a cutting edge loses its sharpness |
| Cutting edge route | Polycrystalline diamond edge or a coated carbide drill | The two routes differ in how the working edge is formed |
| Hole diameter range | Every nominal diameter in the request, not just one size | Edge geometry and drill rigidity do not scale linearly across a wide diameter range |
| Diameter tolerance | The tolerance stated in the enquiry, for example +/- .005 in | A single tolerance applied across many sizes constrains both edge and drill body |
| Hole quality criteria | Acceptable delamination, fuzzing and chipping at entry and exit | These define whether a standard edge is sufficient |
A useful enquiry gives enough information to select an edge geometry rather than just a diameter. Aerospace composite drilling requests commonly arrive with several nominal diameters, one diameter tolerance applied across all of them, and a choice between PCD and coated drills left open for the tool maker to advise on.
| Information to provide | Typical form | What it is used for |
| Material designation | Aerospace-grade CFR / SMC composite system | Selecting the cutting edge material and geometry |
| Nominal diameters | Nine nominal diameters listed in one request | Grouping sizes that can share one tool concept |
| Diameter tolerance | +/- .005 in across the diameter list | Checking the tolerance against the proposed drill body |
| Tool route | PCD or coated drills, both requested for comparison | Comparing two edge options against the same holes |
| Application | Aerospace composite drilling | Setting the hole quality expectations at entry and exit |
We manufacture PCD drills for composite drilling with the hole quality requirement as the starting point. When a request comes to us, our engineering team reads the laminate system, the diameter list and the stated tolerance together, because an edge that cuts cleanly at one diameter will not automatically behave the same way at another.
| Design focus | What it targets | What it means in production |
| Sharp, shear-oriented cutting edge | Fibres pulled out at the hole exit | Aimed at limiting delamination and fuzzing at breakthrough |
| Wear-resistant polycrystalline diamond | Abrasive fibre and filler content | Designed to hold edge sharpness against abrasive laminates |
| Diameter-specific drill body | A wide nominal diameter list under one tolerance | Each size is reviewed as its own rigidity and force case |
These are design targets, not a performance guarantee for every laminate. Hole quality also depends on the material system, the machine condition and the cutting parameters, which is why we ask for the full diameter list before recommending a configuration.
Start with the information in section 3. Once the laminate system, the nominal diameters and the diameter tolerance are clear, the open questions are usually the edge route and the geometry for each diameter group. Our engineering team reviews these together and recommends the PCD or coated configuration that fits the application.
We do not treat a long diameter list as a single tool. Nine nominal diameters under one tolerance can behave as several distinct drilling cases, and grouping them correctly is what keeps hole quality consistent across the set.
Delamination in CFRP and SMC composite drilling is a cutting-edge problem at the point where the laminate is least supported. A sharp, wear-resistant PCD edge is specified to limit delamination, fuzzing and chipping, but the right configuration depends on the material system, the full diameter list and the tolerance the holes have to hold.
Tell us your laminate system, nominal diameters, diameter tolerance and hole quality requirements, and our engineering team will recommend the PCD or coated drill configuration that fits your application.
Because a polycrystalline diamond edge stays sharp against abrasive fibres and shears them instead of pulling them from the laminate. That is the mechanism behind reduced delamination, fuzzing and chipping at the hole entry and exit. It is a design target rather than a guarantee for every material system.
Near breakthrough the remaining layers have no support underneath, so the drill point pushes fibres apart instead of cutting them. A rounded or worn edge makes this worse by rubbing rather than shearing, which also produces fuzzing on the hole wall and chipping at the entry.
There is no single answer without the application data. The choice depends on the fibre and filler type, the diameter range, the stated diameter tolerance and the hole quality criteria. Provide those details and our engineering team will recommend the configuration that fits.
The material designation, all nominal diameters, the diameter tolerance applied to them, the preferred tool route and the hole quality requirements. Aerospace requests commonly list several diameters under one tolerance, for example nine nominal sizes at +/- .005 in, with both PCD and coated drills requested for comparison.
