At Bray, we use a slotted spoil board with our CNC Router. This enables us to attach clamps to a t-slotted table below:
In the past, we have used the Rockler Hold Down Clamps to secure material. However, this clamp can damage our router bits due to collisions with the clamps:
We 3D printed clamps to mitigate this issue. The PLA and ABS plastic clamps prevented damage to the bits from collision:
However,the plastic clamps cracked under the clamping forces:
The clamps were then printed with a combination of nylon and carbon fiber on a Markforged Mark Two 3D Printer:
These clamps were much stronger and able to flex without cracking. The clamps were tested on the mill to simulate a bit collision. The milled carbon fiber broke into fairly large chips. There was a concern that the carbon fiber and nylon material might melt onto the bit. However, the bit came out clean. Check out the video clip below:
Testing carbon fiber clamp on mill