I have been working with a SC600 for about a month now and am having recurring problems with the refernce positions shifting in the x and/or y axis during 3D printing and CNC machining. I will be in the middle of a job and the entire x or y axis will shift either positive or negative in either the x or the y direction. It is a step shift in the entire coordinate system as the job will continue on with the new refernce points. After shutting down and looking at the x and y locations I find that the reference positions have jumped. I checked pulleys and belt tightness and see no problems.
I put a dedicated fresh laptop on the system and this reduced the problems with the CNC operations as long as I slowed down the feed rate to 90% in the Win NC PC controllers pop up window. I then started operated the 3D printer and am finding the same problems in the middle of the print. Again the only solution seems to be slowing down the feed rate after starting operations.
I believe all of this points to a communication issue between the SC600 controller and the laptop. I am thining that shifting away form the USB interface and using the parallel port module and or adapting the USB I have to a parallel port might help the problem. Is this a common issue with Win NCPC and the USB control. I have seen it with two sparate laptops and the SC 600. Would MACH 3 help eliniate this proble? Or is there a problem with my SC600 "brainboard"?
Any help would be appreciated.
In german forum somebody mentioned that this could be caused by a problem not to have the machine grounded and connections having different electrical potentials or having statical overloads especially if you mill plastic.
I had no such problems in WinPCNC or Mach3 so far (connected via USB).
Steppcraft 600/2 + HF500 + SwitchBox + Laser + Schleppmesser
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Thanks for the feedback. I thought at first that it might be a mechanical problem but it shifts the reference position in both the x or y or z direction (it varies) and shifts it positively or negatively and affects only that point. Once it shifts there is no other effect except that now the second half of the part is now being machined or D printed either to the left,right, above or below of where the first half was. Creates some real interesting looking parts. Slowing down the feed rates to 90% of the default in WIN NCPC definitely helps. Will have to check what mm/s this value is.
The grounding idea may be something to look at. I have no idea why it would just reset the reference positions but may have something to do with locating the stepping motors. Anyway, that is easy do and a quick fix if it works. Mechanically I have gone though the SC600 and it works fine otherwise with the random shift occurring (usually when I have just left the room). It did do it once while I was watching it with no apparent outside cause, i.e. hung up cable, jammed axis, tight filament, etc.
I'll force a ground on the chassis and gantry and see if it helps. Thanks for the suggestions,
Maybe it is a resonance issue, something like described
. 3D printing shouldn`t create much load on the machine, maybe this contributes to the problem. Maybe acceleration value together with the used feedrate make the motors work at an unfafourable speed region or something. I have noticed missing steps on my machine at high load or going at 700-1000mm/min (too little testing to make any assumptions about this feedrate region, could also be due to high load).
Stepcraft 600SF (version 1) parallel port
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I have just started having a problem with y axis shifting during cutting. Part way through the job the y axis shifts by several inches. It just seems to redatum, there are no issues with belt slippage, the axis just smoothly shifts. I tried a couple of different tool paths and the same thing happens. This happens even if cutting in fresh air.
I just recently re aligned the y-axis and lubricated the machine. It jogs along without any problem.
If your Y-axis movement loses datum when running at normal programme speeds but not when jogging, then almost certainly it is over tight adjustment of rollers or poor alignment of the Y axis leadscrews. It should be relatively easy to move in Y by pulling on the drive belt over the full range of movement of the gantry.
You may have to "retune" the Y axis to achieve the necessary freedom of movement. It is all too easy to overtighten the rollers - from personal experience!!