X-axis slow down while cutting file??

[blackhawk]

I was cutting a 3D file last night where I am rastering in the X direction. The piece is 3" wide x 64" long, so the X movement is along the 64" length. I watched the cut the first 5 minutes and everything was going fine. My move speed was set for 3 IPS. The file should have taken about 1-1/2 hours to cut. After about an hour I checked on the progress and I was only at about 40% completion. I started watching and the X movement would slow way down to maybe .5 IPS in places. This would happen in places where no Z movement was required. At the edge of my final cutting, the machine was making full 64" length passes where no Z movement was required. That whole distance it would move at the very slow speed. I then manuaully raised up the move speed with the keyboard. It didn't do anything at 3.1 IPS, then when I clicked again at 3.2, it took off full speed. I could back it back down manually to 3.0 and it still ran fine. Then when it got to the end and began to change direction, it would slow down again, until I manually adjusted the move speed.

I have never seen this before. The Aspire file looked fine when I checked the code. I am running the pre 3.8 control software. Any ideas what this would be?

After the file finished, I did some manual MX commands at 3.0 IPS and it was fine.

[jerry_stanek]

You could try the shift and greater then keys to change your speed in the X, Y

[Jerome]

I had almost the same thing happen last week. I was cutting a simple profile in mdf when the bot slowed down to a crawl. I tried speeding it up with the shift> keys but it kept moving at the same speed. It did finish the job but it took way too long and the bit was screaming from the slow feed.

I am also using 3.8.6

If it happens again I will install 3.8.8 to see if that helps.

Please post any fix you come up with.

Jerome

[blackhawk]

Jerry - I did use shift and > key, that made it speed up to the correct speed. But when it went to the next line of code, it slowed back down. I have had the machine for many years and never saw this happen. I have been running the same control software version for at least 18 months without a problem.

I also checked my efficiency and I am at 85.7%, which is pretty good.

[bill]

When the move slows, do a "SHIFT>" and then a "SHIFT<". This should bring your speed back to the programed speed (does for me). From talking to Ted the issue arises from (an example) the difference between 0.001" move command and ShopBot's minimum step ability of greater than 0.001". If you relocate the same vectors to another location on the same work piece you will have a greater than 50% chance of this slowdown not happening.

Per Ted..... work in progress.

Bill

[Brady Watson]

Using <shift> to alter speed should be used with some discretion - It does not refresh the command buffer and ramping is not recalculated. Only an interupt (pause in file, S key, space bar etc) will cause the command buffer to be refilled & look ahead (including proper ramping) recalculated. Use it sparingly. If you go more than 2 speed points you are asking for it with jerky moves.

If the tool slows down during the file, and you are running pre-3.8, I would take a look at your VR settings and make sure they are in the proper range. Post up a screenshot of the 3D file you are cutting & your VR fill in sheet & I will take a look.

-B

[blackhawk]

Brady - Here is a rendering of the 3D file and my VR settings. Thanks for taking a look.

[blackhawk]

Anyone see anything that may be off in my settings?

[dconroy]

I've been seeing the same issue with my PRT Alpha when running 3D parts. Any resolution on this?

[Brady Watson]

Don,
Please post a screenshot of your VR fill-in sheet.

-B