If a cnc could hold a mat cutting blade so that the plane of the blade was at a 45 degree angle to the mat with a pointed end of the blade centered under the z-axis; pushing the blade in 1/8 to 3/16" and moving it along the x or y access with the sharpened edge leading- it would make a 45 degree bevel cut in the mat. If rotated on the z axis 45 degrees and repeated in accurate measure on each of the 4 sides, it would cut a beveled mat opening in the larger piece of mat. The blade holder doesn't necessarily need to be pushed in- it could also be on a pivot and rotated in - the way it works on my manual mat cutter. I am new to cnc design. I have struggled to come up with anything that is not really complicated or cumbersome. I ask please for suggestions or references - oh a design would also be nice . Here is a blade holder that may help you understand how the blade is held - and may assist in coming up with ideas. Mat board varies -about .055 to .12 inches thick. Thanks in advance - please let me know if you have any questions. Kirk
Thanks, I've researched "drag knives" but a Drag Knife won't do it. A. drag-knife will not cut 1/8 mat board reliably. 2. drag knife is 90 degrees to mat surface and will not bevel. 3. Once you go from 90 degrees to 45 degrees you can't just insert in to the board with a simple down action.
Sorry, my bad. Wasn’t reading it properly. What you seek is fully possible it’s just not likely there’ll be anything off the shelf to solve the problem. But actuating insertion of a blade at an angle can be done with a solenoid or a servo and an on/off command. We will just need to see the actual cutting parts you have to work with in order to get a better idea of how to attach them.
Thanks. The picture I provided is the blade holder- this is what it goes into the tool head I need help with. The actuator/servo/solenoid will be part of that custom-tool-head- that's not the hard part- its the tool-head-designs- what I've come up with so far are just way to clunky and complex.
Hi Kirk, If I'm right, you want to cut something like the first cut on this video: To get a bevel cut you need to lower the blade into the material in 45 degrees. As @Rick 2.0 mentions, it might be possible with on-off command. But I think there is a second part to this. You won't be able to make the cut like a drag-knife because the blade inside the material will turn out of the drag direction. Yo will need a tangential control for the blade. An additional axis that rotates the blade and keeps it in cut direction. Adding this axis to an openbuilds machine is easy, but controlling it is not. Big industry knife machine controllers calculate the additional axis direction from the x-y direction. I don't know any cheap controller that can do this. (Mach 3 might be able to do it.) Or maybe it could be addressed directly in g-code but you need a software that creates such a code. I would be very interested in a machine with tangential control as well.
OpenBuilds CAM handles the swivels of a blade on a bearing automatically. no motor needed. It calculates the offset move to make the tip of the blade follow the correct line: It even calculates through corners
Hi Peter, that's true for vertical drag knives, but there is a bevel knife in question. Imagine the blade is inside a 3mm thick material in 45 degree tilted from vertical. There are complete different forces on the bevel blade compared to a vertically inserted one. Moves on the corner definitely would damage the material or snap the blade.
Is there a setting for material thickness? I use foam core that is 4 mm thick. to pivot the blade the knife must go to the top pivot and then go back down. I use OpenBuild CAM generator and cannot find a setting for the material, nor in the control software
Not at this time, zero on your spoilboard/cutting mat, so it knows how deep to cut (all the way down to spoilboard/cutting mat)
None, as its not an intended use case of OpenBuilds CAM - its a very entry level, get you started tool. For more advanced work, use a more advanced CAM.
Hello, I too have been hunting for a mat cutter tool for CNC. Did you manage to make any headway? My research has brought me to a Tangential oscillating knife. But I can't see any for the Openbuilds CNC design.
