Hey All New to the forum and CNC in general, I was given an OX mechanical kit as my friend never got round to building it, spent the last few days building it and getting it up and running. I am using the openbuilds control software and after using the wizards to setup steps everything seems fine, attached a pen and had it draw some squares and circles all within 0.2mm tolerance, well using a felt tip pen and a little bleed it may be +/- a little more or less. I decided to do a spoil board flatten job, I am using a 32mm bit but having lots of issues, and I think all of them lack of experience with CNC. My issues are Bit burning wood ( I am using a Matika RT0700CX4) When cutting MDF should the Router RPMs be higher or lower? Bit going deeper as it progresses, at first I thought I didn't have the collet tight enough, but the bit is solid in the collet, it looks like the Z axis is moving down as the bit is cutting, so I had it set on a 3mm cutting depth but at one point the bit was easily 10mm deep. It doesn't happen all the time The bit also seems to be creating steps as though the bit is at a slight angle but everything looks square. Cheers Jamsie
On my phone so not so easy to give you direct links. Search "tramming" (magnifying glass) for discussions on adjusting the alignment of your router. You don't say what feeds and speeds you are using but if you are burning the spoil board then your speed (router) is too high and your feed too low. Your DOC (depth of cut) is too high for a bit that size (bit can cope, machine framework will flex under the forces involved). For surfacing the spoiler board I take the lightest cuts I can (don't want to use it up any quicker than needed) - about 0.5 mm per pass. If your Z axis is moving when it shouldn't I would expect it to show up with the pen - could be the bit is pulling itself into the workpiece. If that's not causing the Z axis problem then you need an expert on OB control and the blackbox (not me!) - someone's sure to be along soon. Alex. PS - welcome to the forum!
Hi Alex Thanks for the reply, I will look into these suggestion when I get home tonight, I think the feed rate was set at 800 but I have no idea about the router as it only has a dial indicator and it was set on max and the book says 30,000 rpm at that. 0.5 mm ok will try that. It was fine on the Pen test. I am not using a Blackbox, just using the cheap Mega and GBRL. As I say new to CNC so lots to learn. Jamsie
This might be useful - it's a guide for a 1/4" bit in a variety of materials, but doesn't say what sort of bit! Also has the dial settings for Makita and DeWalt routers. Speeds and feeds Alex.
After you pointed out my error on the blackbox I re-read your post more carefully. You said you started with an Ox mechanical kit. Did that include stepper motors? What motors are you using and what stepper drivers and power supply? Alex.
Hi Alex My friend had stepper motors and drivers too, the steppers are Nema 23 2.8a 126N and the Drivers are TB6600 and my PSU is a 12v 20A supply. Jamsie
Lower. I would probably set it in the 8,000 to 10,000 rpm range. If it is still burning at low speed, you need to speed up the feed rate. May be the drivers (too hot or faulty) or the power supply (most use 24V) but could also be a faulty setting in your configuration file.
