Ormerod - Y axis moves un proportionate

I updated the latest firmware ( "RepRapFirmware-065b-07-05-2014" ) for my ormerod.

Since then my y-axis is moving unproportionately. When i give a command for +10 on pronterface it moves about 50mm. And it covers the entire axis if i give the +10 command 4 times.

Due to this issue i can't run any file. Even when I give the command to home y axis it touches the extreme end and the motor is still running , so it tries to move ahead.

Has anyone faced similar issues? Is there any step that I was supposed to do after updating firmware?

Edited 1 time(s). Last edit at 05/13/2014 03:11AM by Rishi.

Hi Rishi

Update to the latest 0.65d version. Also, you need to use the updated config.g in the current firmware. You really need to update all the files on the SD card with those from the github repository. The problem is caused by the way the hot end is defined (it's now T1, rather than T0). We found that the M92 (set steps per mm) for the extruder gets applied to the Y axis, when T0 is set! This is fixed in 0.65d.

Ian
RepRapPro tech support

I'm also having problems with my Y-axis moving at random. I'm not seeing any "humping" of the drive belt, so I don't think its too loose. Can the belt being too tight have the same effect? This is happening in about one out of every four prints. Reprinting the same file will usually work perfectly.

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Crouchy
I'm also having problems with my Y-axis moving at random. I'm not seeing any "humping" of the drive belt, so I don't think its too loose. Can the belt being too tight have the same effect? This is happening in about one out of every four prints. Reprinting the same file will usually work perfectly.

I've had similar problems in print, but always due to a specific belt being a little loose and jumping a notch on the gear when catching on something like a piece of plastic that curled upwards when cooling.

Crouchy, it's not the same issue. See: [reprappro.com]

Ian
RepRapPro tech support

Hi Rishi..... Could you post a copy of your config.g file for us to look at... It might be a silly problem in that.

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droftarts
Crouchy, it's not the same issue. See: [reprappro.com]

Ian
RepRapPro tech support

Ian,

I went back and had a look at my recent stepped prints and they were all at the top of an arch. I had noticed that the prints do tend to curl up at this point, but in most cases the edge would melt back in to place when the nozzle came back around.

I will try dropping the temperature a bit. I had some issues finding the sweat spot for this glow in the dark filament.

I was thinking of printing KimBrown's Big Blue 360 and trying his probeless setup. Do you think the better cooling would also help in this instance?

Thanks for your help
Crouchy

Hi Crouchy

Extra cooling may help, but also may be worse; it's about how the plastic reacts as it cools. Extra cooling definitely helps with bridging, but I'm not so sure about overhangs. It *should* mean that the lower layer is cooler, so the next layer can't distort it as it shrinks, but it may also be that the increased speed of cooling of the *current* layer causes it to warp! The print temperature is also important. But generally, the more cooling the better for these situations.

Ian
RepRapPro tech support

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Crouchy
I went back and had a look at my recent stepped prints and they were all at the top of an arch. I had noticed that the prints do tend to curl up at this point, but in most cases the edge would melt back in to place when the nozzle came back around.
Crouchy

This is a common problem for me also - the corner edges of the top of a closing horizontal hole or arch curl up, and that sometimes catches the nozzle during a move and causes the stepper to miss a step. Cooling the nozzle would probably stop the curling, but I don't want to do that for the whole print, and I don't have a second fan. My solution is not elegant or convenient but it works. I watch the print as it gets to the problem layers, then as soon as it has printed each edge, I quickly push the curled-up edge back down with the blade of a screwdriver as soon as the nozzle is out of the way during the three or four problem layers. If you can get in quickly before the plastic has solidified it can be pushed level very quickly - takes a bit of practice if the nozzle doesn't stay away for long! I sometimes have to ensure when slicing that I have oriented the part on the bed to give easiest access to the problem areas of the print.

Some day I will fit a second fan or use some other method to put a directed air jet on the nozzle at only the required times. Slic3r can switch on a fan for bridging, but the problem occurs a few layers before the bridging layer so arranging for the G file to send fan controls at the appropriate time may be problematic even if you have modified the printer mechanically. I don't want to cool the nozzle all the time because I fear that it would result in weaker bonding between layers.

It is also possible to prevent the issue by putting either a notch or a flat at the top of a hole or arch - but obviously that is not suitable for all designs.

Dave
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Edited 1 time(s). Last edit at 05/14/2014 09:59AM by dmould.