Messages

31

General Mach Discussion / Re: sizes aren't correct anymore please help !

« on: December 21, 2014, 11:54:26 AM »

Thank you all for the suggestions and support . Love this forum

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General Mach Discussion / Re: sizes aren't correct anymore please help !

« on: December 20, 2014, 09:11:47 PM »

I was just about to start shopping for new drivers. I'm trying not to throw crazy money into this machine as I'm saving up for a tormach.today I redid the linkage setup for the motors to ball screw and still nothing . I got fed up and decidedown to play with the steps per setting in the motor tuning. It was previously at 8050 and was leaving .02 after a 2" span. I backed it off to 7982 and it's right on and weirdly enough didn't affect short distance accuracy.  Perhaps is was my dial indicator the entire time not being that accurate ? It was after all from harbor freight

33

General Mach Discussion / Re: sizes aren't correct anymore please help !

« on: December 19, 2014, 04:46:46 PM »

Heres the latest update. I ran through and checked all the wiring to the bob and drivers and all seemed good and tight. I then created a new profile and started from scratch and still off by .020 . Has to be my machine then right? I'll be working on it tomorrow tearing it down and seeing if I can find a problem somewhere. What mechanically would cause it to lose .02 over a 2" travel but be able to return to zero without any backlash? This is killing me. I hate taking the machine apart.

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General Mach Discussion / Re: sizes aren't correct anymore please help !

« on: December 18, 2014, 11:25:42 AM »

Actually now that I think about it I have a g40 in the beginning of the program

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General Mach Discussion / Re: sizes aren't correct anymore please help !

« on: December 18, 2014, 11:23:44 AM »

I thought about that too but when I just manually cut the aluminum to a specific size using mdi it was still offor by about .020 . I guess I can try typing in g40 then try manually cutting it again

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General Mach Discussion / Re: sizes aren't correct anymore please help !

« on: December 18, 2014, 09:37:05 AM »

No. It's never been resharpened. It appears that all my measurements are off on these parts including the hole spacing .

37

General Mach Discussion / Re: sizes aren't correct anymore please help !

« on: December 17, 2014, 06:28:33 PM »

Tomorrow I will try and make a new profile and pray that it fixes the issue.

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General Mach Discussion / Re: sizes aren't correct anymore please help !

« on: December 17, 2014, 06:13:19 PM »

Thank you both for the reply . Today I changed the kernel back to 25hz with no results. Heres where it gets really weird. I started to second guess my programming so I had a piece of aluminum that was held in the center by two screws, I milled the left side and set it as my x0. I figured ill manually mill it to a certain size just to be eliminate if its my programming or not. I then told it to move x2.375 and milled the right side. This part should be 2" exactly. Nope it was at 2.020. Ok must just be the motors off right? Put on the dial indicator yet again and moved the axis .100 and was right on. Went back the other way to check for backlash and was dead nuts. I then moved it .900 and it appeared to be off be .004 but returned back to .100 with no problems. ?I checked the cutter diameter thinking I accidentally put the wrong one in but its a 3/8" cutter.  Can a corrupt xml file be the problem in this case?

39

General Mach Discussion / sizes aren't correct anymore please help !

« on: December 16, 2014, 05:39:48 PM »

I'm scratching my head here with a situation I'm currently having. Ill start from the top. I have a benchtop grizzly mill which is converted to a cnc with double nut ball screws, nema 34 stepper motors, microstep driver (ebay). This machine ran great for the past year but recently I've been having problems with motors stalling. I quickly jumped to the conclusion thinking it was just my motors were out of wack and stupid me started changing everything around with the motor tuning and mach 3 setting to get it up and running again. Needless to say it was my ways that needed the adjustment not the electronics. I believe I changed all electronic settings back to the way I had it and continued on making parts.

Heres my issue. I make and sell small aluminum covers to a local company. The covers are made from aluminum and measure .250 thick x 2.43 x 1.73 . I drill all the blanks first then they got bolted to a jig so I can do the outer profile to that size.  My sizes are coming out around 2.46x 1.75. I though maybe its just the motor tuning but using a dial indicator I'm within .001 with no backlash, I then changed my steps per on the microdriver from 1600 to 800. Same exact results. It can't be the program since I've used it hundreds of times. I use the exact same cutter every time. Would the Kernel speed affect this in any way? I'm currently at 45000hz and I believe previously I was at 25000hz

 

40

Third party software and hardware support forums. / Thinking of switching to a closed loop system?

« on: November 17, 2014, 05:54:05 PM »

I've built my cnc mill about a year ago and since then made many many parts. During that time however I've certainly had my share of set backs. Most of them involved missing steps. My problem would happen if I run a large quantity of parts without letting the machine rest. For example, a part I designed required three holes drilled 1" deep. I was peck drilling each hole and the entire cycle time was around 1 minute. I can run about 20 parts with no problem but then all of a sudden I would hear that "squealing" noise and sure enough the z axis loses its position. If I let it rest, reset the position I would be good for a couple more parts. My question is if I go with a closed loop stepper system will this indeed solve a missed step problem? Not only am I aggravated cause I'm constantly hovering over the e-stop button but sometimes I ruin the part in the process. My current setup is a grizzly 1006 bench mill with Nema 34 Motors, running at 800micro steps per. Anyone have the closed loop system?