Back to CNC work. Is there a CNC engineer that can better explain to me the difference in running the 50W verses the 200W CNC head? In the old 50W guidance, Wood (Janka hardness of >1000 which includes walnut at 1010) should be at a work speed of 420 mm/min for the V-bit in relief mode. The newer 200W CNC guidance is 300 mm/min for walnut and the V-bit. There are similar recommendations for the other bits. I queried SM, and the response, while acceptable, was a little short on explanations and basically said the âsettings take into account not just power, but also spindle speed (RPM). A higher RPM on the 200W unit might require a slower feed rate to ensure the bit properly engages with the material, preventing excessive heat buildup or bit wear.â and to âFeel free to experiment with different settings based on your real-life usage as well!â
I invested in the 200W for âfaster and betterâ work. Not being an engineer, I donât know how far I can push the 200W without damaging it or the bits. What are the signs of âtoo fastâ for conditions?
[A350 with the bracing kit installed]
Any further guidance is appreciated. Thanks
I use the recommened settings as starting point and depending on the material I set it to a higher speed on the touchscreen.
If the recommened settings are slower, is it more step down (carve deeper per feed)?
Depending on the material it could lead to blocking of the tool (the toolhead is protected against via software but your carving process is lost), or breaking of the carving bit, rubber marks and bad surface finish.
You can hear it if itâs no normal sound.
I donât use extreme feed speeds or step downs because itâs too loud for my environment so, hope this helps.
I used to operate commercial grade CNC routers with spindles that range from 1.5kw to 5.5kw in cutting power for a decade so Iâll chime in. The jump from 50w to 200w sounds like a big jump, itâs a 4x power bump, but itâs really not going to perform much better in hard materials as you really need a lot of torque behind your cutting, which really isnât present in either 50w or 200w spindle. The 4x power difference will manifest itself in softer materials like foam, basswood, mdf, etc, but not necessarily harder materials.
Typically with a more powerful spindle you can cut deeper passes and keep the same feedrate as the weaker spindle, or keep the depth of cut the same per pass at faster feedrates. In the case of the 50w vs the 200w, you should be able to either double the cutting speed OR double the depth of cut in softer materials, but probably not both at the same time, unless weâre talking foam or balsa wood.
If your straight cuts arent coming out straight, reduce the depth of cut or feedrate. If your cuts are burning the wood, youâll want to make sure that the end mill youâre using has 2 or 1 flutes so that the chips have ample room to get out of the way. You can also reduce the depth of cut by half. Now, reducing feedrate should your last resort as keeping the endmill in one spot for too long can cause excessive heat and create burn marks.
For cutting hardwoods you really want a spindle that has an RPM of between 18k to 24k, which are typically AC power in nature (so they require a VFD) and have a power raiting of 800w. I really hope Snapmaker releases a dedicated CNC machine at some point, even if it only comes with a 600w DC spindle itâll be a nice upgrade, though if they can manage to pair it with an 800w AC spindle or allow the attachment of a 1.25hp hand router, like a Dewalt 611, itâll be a really capable beast.
With all this said, Iâm not claiming the 200w spindle canât cut hardwoods, but itâs not really ideal for it. All you can do is start from the recommended settings and test from there until you can narrow down settings that youâre happy with.