How Should I Machine This?

Absolutely, in getting it working I had one servo runaway with the belts attached, magmotors at full spin are terrifying fast, I was luckily able to estop before the axis hit its endstop but in my mind that could have cracked the cast iron and I"d have a 3000lb paperweight in my basement.

I'm putting /huge/ rubber bumpers at the ends of travel due to being paranoid, but this thing is /awesome/ compared to the hobby mill, even at the above "conservative" 15ipm / .1 doc / less than half cutter engagement I can make the run for that part in the first post in under 5 minutes, that was like a 20 minute job before, plus fixtures/indicating because I could never get a big enough vice in the little one, and I'm not even going /fast/ yet.
It is pretty exciting that I am this close to getting it running, I'm close to a year in on this project, hah.
 
I've got this tuned out now, I went to a larger, sharp, 3 flute cutter which seems to have removed the dive

Did some experimentation climb cutting, and even with a 1/4" ballnose not cutting much at all it wanders a little, so i'll stick to only using it for the final finishing pass. but moving on to more complex cuts and all is going well!
I'm having some minor accuracy issues with some parts, but I believe that is leadscrew wear which I can't correct for until I get good home switches.

wat.jpg
 
Sounds like you are on the right track. :encourage: That is a complex part, looking good!

I'm not sure how home switches will help compensate for lead screw wear. Can you explain what you have in mind?
 
JimDawson said:
Sounds like you are on the right track. :encourage: That is a complex part, looking good!

I'm not sure how home switches will help compensate for lead screw wear. Can you explain what you have in mind?
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In mach3 you can create a grid basically, pick a spot on the table, tell it to move 1", then measure how far it actually moved in order to measure the wear on your leadscrew/nuts, off the top of my head I don't remember what the menu was (screw mapping?), but once you create the measurements mach3 can compensate for them so your parts dont end up slightly squished or stretched.

But anyways, in order to map out that grid and have mach3 know its relative position according to it, you need a home position for mach3 to reference. Right now I don't have a home position at all so it has no idea where it actually is on the table, just from its work home reference point.

Ive also noticed that I get a "moan" from the right side of the y axis at a certain point in its travel, only when moving in one direction... which I need to figure out.
 
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Ahhhh.... That makes sense. :eagerness: I remember seeing that screen.

Metal said:
Ive also noticed that I get a "moan" from the right side of the y axis at a certain point in its travel, only when moving in one direction... which I need to figure out.
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Strange. It is possessed? :cautious:
 
I may be wrong but I thought I read where Mach3 has a limitation on backlash compensation. In other words if your backlash exceeds the maximum allowable then BL compensation doesn't work at all or Mach ignores the incremental backlash that exceeds the maximum allowable.

Tom S.
 
Do a Google search for 'mach3 backlash compensation'. A lot of info on it.

I see double nut ball screws in your future :)
 
I dont think its haunted, I think its the ways binding or some stuff got into them or wear on the ways (but they still had scrape marks so that would be strange), weird that its only in one direction.

Backlash compensation is /fine/ I have it setup and it works great, the only issues I ran into was I had a mm indicator and imperial screws so I ended up with too many significant figures doing the conversion and ended up having to round it for mach3 to work right.

What i'm (vaguely" seeing is my parts end up being a few thou longer than they should be, even if only traveling in one direction, its not really a big deal for the kind of stuff I make, but I should probably fix it.
 
May have figured out the noises, adjusting the gib appeared to do nothing, but adjusting the y axis belt did, it appears the servo belt drive is putting too much downards strain on the leadscrew or somesuch, i'll see if i can order a belt with one more tooth
 
Cool! One little step at a time, but you're getting there :encourage: One of these days some pictures of your machine would be a good thing. :)
 
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