Tools for CNC Machining of Composites
If you ask anyone who has had the dubious pleasure of working with them, composite substrates are some of the most challenging materials to machine. It is not so much that the individual components (binders and fillers) are necessarily hard to machine, it is more that the cutting properties of the components are often so different that it is impossible to design a tool that will cut the composite with anything near optimum results. The best that you can do is engineer a compromise that provides acceptable cosmetic results with reasonalbe tool life. Fortunately, our use of premium grade submicrograin tungsten carbides and vacuum deposited coatings have shifted the equation enough that it is now possible to get very good cosmetic perfrormance coupled with an extended life.
What are depth rings?
What are depth rings and what tools can have them?
Depth setting rings are plastic collars that are securely pressed onto the 1/8 in. shank of a drill bit, end-mill, router bit, or similar rotary cutter. There is no charge to add the rings, but the user is cautioned to make sure that their equipment is compatible with their use.
Most PreciseBits 1/8 in. shank bits are available with or without depth setting rings. Bits that can't have rings are:
- End-mills smaller than 0.005" (0.127mm)
- Shanks longer than 1.50" OAL
- Cutting depths or necks longer than 0.50"
- SRD kerf cutters (MM5D8)
How do they work and why would I want them?
The shank side of the ring (top side in the picture to the right) is accurately positioned (d ±0.004 in.) relative to the tip of the tool. If the shank-side of the ring is pressed against the collet when the tool is loaded, the tip of the bit will be a known distance (d) from the face of the collet. Knowing this distance, the programmer can plunge the tool, confident that the depth of cut will be as expected and will remain the same no matter how many times the tool is changed. If all of the tools in the programmer's magazine have been fitted with depth setting rings, an automatic tool changer can load and unload tools with the tip of each one the same distance from the face of the collet.
This is especially helpful with micro-tools where "touching-off" on some reference surface to calibrate the tool height can damage or break the tip of the tool. Rings also find widespread use in inlay pocket cutting where relatively large diameter cutters are used to "hog out" basic shapes, followed by much smaller diameter finishing bits that clean up the edges, sharpen the corners and add fine detail to the finished part.
LPKF and T-Tech
The most common value for d is 0.800 in. (industry standard). However, with the advent of mechanically etching printed circuit boards in the mid 1970s, a new standard was implemented for the special purpose tools developed for this application.
Today, only machines made by LPKF and T-Tech adhere to this special standard. Systems from AccurateCNC, MITS, Sun and EverPrecision are compatible with the original industry standard depth of 0.800 in.
Tool families: DC208, DC2M8
Our drill bits are available in sizes ranging from 0.005 in. (0.125mm) to 0.250 in. (6.35mm) are available from stock. Diameters down to 0.001 in. (25 micron) are available upon request. Slotting drills and high aspect ratio tools are available on a special order basis.
Tool Families: EM2D8, EM2E8 & EM2E4
Designed specifically for the dimensional signage and engraving markets, 2-flute solid-carbide "V" cutters feature polished, high-rake cutting edges capable of producing a surface finish suitable for edge-lit transparent signs and plaques. Edge finishes are typically smooth and free of chatter.
High flute volume and precisely shaped ejection paths support high chiploads in a wide variety of sign making substrates. Precise "V" angle formation (±0.2°) permits either single-pass or multi-pass cutting without fear of steps or streaks.
Tool families: RCD08
Our 6-flute diamondcut routers feature a cross-ground configuation that features a primary grind that creates a down cutting action on the tooth face to minimize lifiting forces. The secondary cross grind creates an up-shearing path for the removal of cutting debris. Cross grinding significantly increases the amount of cutting edge, extending the life of the tool while creating a smooth sidewall finish.
These cutters are our most popular and durable tools for cutting carbon fiber.
Tool family: RC3D8
3-flute tools that have been otptimized for cutting very clean channels and pockets into thin phenolic and phenolic composite sheets. The zero-helix flutes (cutting edges are parallel to the axis of the bit) generate no lifting forces that might defeat vacuum fixturing of small parts.
They have also become very popular for cutting balsa wood sheet stock.
Tool families: RCC08
Our 6-flute chip breaker routers are cross ground at different depths to create well defined up shear debris removal channels (flutes) topped with down cutting serrations. This geometry provides significant overlap between the "teeth" resulting in smoother sidewall cutting although at a slightly lower chipload than a diamond cut routers.
Tool family: EM4E8
4-flute tools designed to produce chatter-free counter sunk holes with no edge fraying in G10, carbon fiber and phenolic substrates. The cutting edge geometry generates virtually zero lifting forces making the tools compatible with thin sheet goods.
ME Lube significantly reduces the formation of potentially hazardous micron and sub-micron sized airborne particulates common when cutting features in PCBs or machining G-10, FR4, carbon fiber or phenolic substrates. The lubricants and surfactants provide cooling and reduce cutting resistance, yielding extended cutter life, reduced burr formation and the minimization of chips and shorts.
An effective solution for removing fuzz, fray, hair and splinters from 3D carvings and engravings in wood, composites and plastics. FuzzBrush is lightweight and comfortable to use.