All - I have been working on something with some help from the R7 group. Now I need your help as well.
This is for all the DIY CNC guys. How often have you tried a feeds and speeds calculator only to find that the results were less than desirable?
I want to create charts for those of us, a reference if you will that will get us a little closer to where we need to be feeds and speeds wise on our DIY hobby grade machines. The best place to start I believe is with feed back from you guys. Please provide as many references as you can in the google sheet linked here. At the end of the study I will release all the results on a blog with charts and graphs and hopefully we can help ourselves and the future guys get as close to that perfect cut as possible.
Fist off I’d change dive speed to plunge rate. I can add my feeds tonight, but i aim for a 0.08-0.1mm chip when i cut mdf. Maybe 0.07-0.08 for hardwoods.
The calculator goes off speed and bit size/rpm. Your depth of cut comes from how rigid your machine, how dull the bit is, and if the bit is flexing.
Well I can’t say I’ve practiced feeds and speeds a much as I should. For instance my RPM is usually 12000 all the time. I’ve never broken a bit or burned wood or bits at that speed using the 40w 52mm Chinese spindle. I typically use 1/8" bits and most of the time I’m using a 2 flute flat bottom bit. What I do adjust is my feed rate. Hard woods I have to slow down to 15-20 ipm. Softer wood like pine and MDF seem to work well at 25-30 ipm. I am sure I could probably get better smoother cuts by adjusting both RPM and IPM but the time I have on my machine is often limited and I’ve always rather spend my time designing and cutting then getting perfect feed and speed. This typically means I have some sanding and clean up to do after a cut. I like what your doing though Brandon and will surely use it when available. It would be cool to maybe have something similar for laser cutters but that sounds like a very different animal. I was running some feed rate test yesterday with my laser, I was able to reduce engraving time on a Hydroflask by more than 1/2. Feeds and speeds can definitely be worth the time to figure out.
@Matt_Herrera Would love to have your input on the sheet, it will hopefully help others. Agreed we do need something for lasers, that might be another sheet for another time.
It seems like you guys are running your machines REALLY slow compared to my feeds? Whats going on there! Brandon, I swore your pine numbers were in inches! lol