Is there anyone with a decent amount of Snapmaker 2.0 CNC experience who can comment on (soft) wood carving speeds and feeds?
I’m trying to carve a 3D star which I will laser cut out (not with the Snapmaker) and inlay into a wooden flag.
I figured out how to generate G-code using Fusion 360 and based the speeds and feeds on what I saw in the Snapmaker acrylic phone holder demo - basically, 400 mm/min, 0.7mm step down, 0.7mm passes using the ball-end mill.
The carving is going well so far, but SO slow. This one star - about 50mm in diameter - is going to take 4.5 hours, and this is just the roughing stage.
Anyone have a sense for how much harder I can push the machine? Any tips on finishing speeds and feeds?
It is a very large subject. If you have any experience with feeding machine tools into materials by hand, you will come to know that the feel and sound of the tool against the workpiece will tell you whether the tool is being being driven beyond its design. This is an entity that is hard to describe but may be known as mechanical sympathy… that is to say that you can hear and feel when a machine is labouring.
From that point of view all engineers will encompass the use of ‘feel’. Machine tools like endmill bits are designed to feed through the work while below the surface of the workpiece. This imparts a load on the bit from the side and if you apply the load too fast or you are using a material that is too hard for the machine’s capabilities, the sideways load may be enough to break the tool.
Other factors will determine whether you can increase the speed of cutting (feed rate) such as how many flutes does your cutting mill bit have. It can vary a lot and normally, there are endmill bits with 1, 2, 3, or 4 flutes. The number of flutes and the helix angle can determine whether the bit is for roughing or finishing and the flute number also has an effect on the strength of the bit. Less flutes equate to a tool that will form large chips easily but the tool bit will have less strength than multiple flutes which will form smaller chips and more of them. This in turn creates the chip load of the endmill bit.
Feed rate and chip load are related so that if your workpiece is producing a large chip load in response to a 4 flute endmill then the feed rate has to be adjusted to take the chip load into account. The following chart may help you to decide upon the chip load of your cutter and you can make the necessary adjustments.
Finally, use some scraps of wood and experiment, based upon the information in the charts and tables. Too high a feed rate speed on softwoods will chew the edges and leave a rough finish. Too slow a feed rate speed will just have you wasting hours doing a single job. There is no substitute for trying it yourself and experimenting because another person’s experience may not be relevant to your situation.