Hello all, I am new to the forum and a complete noob on all things snapmaker. I am using an a350 with the enclosure and rotary module for reference.
I have followed the tips by Skreelink and found them very useful but my brain must have dropped off at some point because I failed two projects and I am unsure of how to fix it.
My question is this… How do I create a project in luban for 4th axis carving and generate a roughing pass and a final finishing pass?
I was able to use the demo lion project and generated the roughing pass but when the job finished I used the bit assistant and it ran the entire roughing pass over again for my finishing pass. This may work for general settings on a softer material like that pink stuff they include with the machine but I want to carve harder material like epoxy resin and need one set of speed, depth etc for roughing and one completely different one for finishing. And if I am only finishing the last 1mm, why should I let the machine run for 23 days (actual run time) for a finishing pass that won’t even touch until the last day?
For the finishing pass you can set the step down a lot larger. Like the radius of your stock material. i.e. if you’re using a workpiece zith a diameter of 40mm, you can set the step down at 20mm. That way it won’t do all that air-cutting first.
@brvdboss is correct, on your roughing pass, make sure to set an allowance in the toolpath setup to leave some material. When you setup your finish pass, increase your stepdown, since it, in theory, should only be taking ~1mm. This is mainly because Luban is not really setup for multiple passes, it has no rest machining (where it calculates another pass from a previous operation). So it has no idea the material is already cut.
OK, I will give that a try. I did not try that because In my feeble brain I thought the step down=plunge. I thought that would be a recipe for disaster. Lol
I will give that a try and post up results. Thanks again.
And I think that is the right reflex as it is exactly what will happen. Just in this case the roughing pass has already cleared away all the material except for the last few mm.
So in reality, the depth of cut will be limited. But it could be significantly more than just the last mm if the milling bit you used for roughing was significantly larger than the final bit as it won’t be able to reach as deep in small pockets and holes. So you should have a look at the particular model you’re creating.
Assume you have a 2mm wide groove in your model that is 4mm deep.
if you use a 3mm flat end bit for the roughing pass, there is no way it can go down that groove (as the opening is only 2mm). So the groove won’t be milled at all. (as the bit can’t enter it)
When you do your finishing pass with the really fine v-bit, it will actually cut a lot deeper than 1mm as the groove is 4mm deep and it is small enough the actually enter it.
So the plunge will be deeper than 1mm in that case.
OK, so as long as I don’t have aggressive settings for my finishing v-bit it will make that 4mm deep groove but it won’t try to do it all at once and snap my bit.
So I can set my step-over and plunge to .001 (super slow, I know) and my step down can be 7mm and when the G code approaches the hypothetical groove it won’t drive 4mm straight down into the groove? It should obey my super slow settings of .001, correct?
Sorry if I seem dense. I really appreciate the help.
The step-over is how much of the previous path will be covered again, or size of milling-bit minus step-over is how much will be milled away from the side. This will have an impact on the smoothness of your surface. For a v-shaped bit this can be small, but 0.001mm is a bit excessive, especially since the machine itself just isn’t capable of that type of accuracy
if you set the step down to that value, (how much to maximally cut away per pass, downwards) You’ll be cutting in the air for a few weeks first. Then there is no use in doing a roughing pass first
The example I gave was a bit extreme, but I don’t think there is any problem with typical models. It’s just something to watch out for in special cases (like models with holes and cavities inside them)
As far as I know, it’s not possible in Luban to set anything else than the step down. (in Fusion360 you can for example tell it to go down in a spiraling pattern to avoid abrupt plunges etc). The only thing you could play with is the plunge speed. (default at 300mm/min, which is 5mm per second)
But if you reduce the speeds too much, you’ll just end up charring your work because the friction will cause a lot of heat which result in burn marks.
I would just say give it a try and you’ll notice soon enough if something is going too fast (or slow) and you can adjust the working speed on the touch screen a bit (or abort the job). It depends a lot on the material you’re working with, the milling bits used etc.
I am primarily working with epoxy resin which sets up really hard and I know the snapmaker is able to handle things like aluminum but this isn’t a Bridgeport, I can’t take huge passes and expect it to perform. So like you said I will have to play with the settings a bit and find the goldilocks zone for this material.
I believe I have a firm grasp on the concept. I will give it the ole’ college try and let you know how it goes.
