Reply with Quote90-120 is a reasonable place to shoot for, more would be nice but also gets you into trouble that much faster. At one point I had my machine set up for 240, then I stepped down to 180, then to 120. Now I have it set for 90 and I'm pretty happy.
Ballpark goals for benchtop cnc?
Is 120 IPM on X and Y a decent speed to calculate for?
I'd presume rapids could be higher until it starts missing steps but as max speed within the torque curve is that a good bet?
What about Z... I'm kind of thinking of using a higher torque/lower speed option on Z to compensate for the mass of hauling that around... does that make sense or do I use the same 120 IPM (or other suggested speeds)?
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Q: How many tools does it take before a simple task becomes a project?
A: Just one. I'm the Tool that turns a simple task in to a project.
90-120 is a reasonable place to shoot for, more would be nice but also gets you into trouble that much faster. At one point I had my machine set up for 240, then I stepped down to 180, then to 120. Now I have it set for 90 and I'm pretty happy.
Maybe I missed it, but I don't see what kind of machine you're considering and what you want to do with it.. In my opinion, rapids are sort of a product of how long the table is. 200ipm rapids on something like an X2 don't make much sense to me, and 90ipm on an IH clone with 30" of X travel also seems inadequate.
In any case, the faster the better - until you start breaking things!
120 ipm on 30" of travel may seem like forever (15 seconds) but realistically how often do you run end to end rapids? Speaking as someone who is relatively new still to the cnc game in terms of operating experience I can say that 120 ipm on my 30" travel in x is more than adequate for me, I probably rapid z more often for tool changes than x or y. This is from a "hobby" perspective where I spend more time usually setting up a part (ie programming, clamping setup, tool setup, etc) than I do cutting. That "lost time" in rapids where the tool isn't cutting just does not matter to me. Part production times aren't a high priority. If they are to you (ie you're setting up a business type operation - same part many times) then by all means aim high - it will pay off.
You don't want to go too slow on Z - as mentioned you usually need Z up for tool changes and its helpful to have the speed there for peck drilling cycles.
Mike
You didn't miss it... I didn't specify. It's essentially a SX2. Travel will be about 6x12.Originally Posted by TiagoSantos
I mostly wanted to know if I was in the ballpark..... sounds like I am.
If I choose a lower speed/higher torque option on the Z axis it would run at about 60 IPM... is that too slow?
Q: How many tools does it take before a simple task becomes a project?
A: Just one. I'm the Tool that turns a simple task in to a project.
It is probably fast for that machine and its construction, I'd be surprised if you ever hit max. Better to have that ability though then to watch the pot boil while the machine traverses from one end to the other.
It really depends upon your expectations and the type of work you do. The reality is in most cases you will seldom hit max velocity on that small machine. Your Y & Z travels would seldom if ever.
If I choose a lower speed/higher torque option on the Z axis it would run at about 60 IPM... is that too slow?
The high torque option will likely lower your chances of missed steps but on the other hand the machine isn't the type where you are likely to leverage that torque. I probably would lean towards 60 IPM instead of 120. That should make for a more reliable machine at the expense of slower max speeds.
To me it all depends on what you are intending to do with it and your experience level. For a hobby machine, 60 IPM is enough, especially if ou don't have much experience. If you are looking at making a machine for light production work then that may be low as any extra time is money wasted. My G0704 is a hobby machine and I have it set for 180 IPM rapids and that seems fine to me. Not to fast and not too slow. On a larger machine like a RF45 I would want at least that, but I worked for many years in a shop running commercial VMC's so I am a bit spoiled. If you are building a hobby machine then consider that anything you want to make can be made with slower rapids, it just takes a bit longer, but in hobby use it probably doesn't matter much.
