Shopbot desktop and cold conditions.

[Hoytbasses]

Greetings:

Just wondering if anyone else has encountered this : I have a desktop that's 4-5 years old. I use it primarily for making guitar/mandolin/ electric bass parts. It's located in my basement which is usually about 57 ish degree this time of year. I ran a big project about 2 weeks ago gutting out 1/2" ply parts for building forms. Probably 25 pieces and zeero glitches.

So this week I went to set the machine up for another job. When I moved the tool with the keypad, it worked fine... smooth motion...Z travel smooth also.

Then I went to zero the x,y axes using that function on the keypad,and the machine was jerky and refusing to zero. I used the keypad to bring the tool to 0,0 the x,y axes.. then tried to run a part. Once again the tool was jerky and 'stuttery' . As the day wore on, I was able to cut a couple small parts. And wa able to zero out the x,y axes using the keypad. No changes to the machine, computer, or software other than the shop being maybe in the high 40's rather than mid-hi 50's in this cold spell.....

Has anyone had issues with the machine not performing correctly in the cold? As i said, I ran a big job with zero issues a week or so and ten dgrees warmer.....

Thanks for your feedback... and Go Patriots!

[cowboy1296]

there was a time when i had to run my buddy with the door open and temps got into the 20's. i never had any issues with it other than me shivering. i now cut with the door closed.

[scottp55]

Humidity is WAY down this week, I'd probably check all my USB connections were clean, and then my grounding for tarnish first?
IF machine won't zero to X,Y limit switches, check for crud everywhere.
My shop has been 15F below normal in mornings, and cracked the door to the house....but thinking humidity and static?
Dumping a gallon of water a day down a recessed area of floor, and can barely maintain 35% RH.

Only time my Desktop stutters is if I try to 0,0 off limits switches before control computer is finished everything in it's start up, OR sometimes If I'm parked at 24,18 and run it...she'll stutter off my Y,18 limit switch.
What oil on rails for regular maintenance?

Check your Packet ET times(UD and read)...are comm speeds good?
mid 40's in the am here in shop..but humidity is difficult to keep up in house/shop.....Check and swap peripherals if possible?
scott

[Brady Watson]

It the spindle or router bearings that you have to be cautious with when running in cold temps. I don't heat my shop year round and some days it might be in the teens-low 20's...in these situations you need to be VERY careful about how you warm up your spindle. Here's what I do:

1) Rotate spindle shaft by hand a few times to get the grease moving.
2) Set the VFD to the lowest RPM possible - making sure the shaft is turning. For gantry tools programmed by SB, the lowest setting is 5,000 RPM - which is WAY too high in these conditions. DT with 1hp spindle, set it to something like 20Hz on the VFD (1200 RPM) and just leave it there for a solid 15 min
3) After 15 min, bump the RPM up to like 3000 RPM and feel the lower bearing lands for warmth.
4) Increase RPM conservatively to continue to warm up spindle.

I'd make my own spindle warm up routine that doesn't shut off after 10min because it is made for tools that live @ room temp. The same reason you don't fire up your truck and floor it immediately, is why you don't fire up your spindle the same way. The special grease in the bearings need to warm up slowly or it will remain thick/viscous and potentially skid and gall the balls and races...the grease at low temps acts like a solid that prevents the balls from spinning and rolling freely.

If you really & truly take the time to warm up your spindle no matter what the weather is, it will last a very long time. Remember, all these non-ATC spindles are throw aways...when they wipe out bearings you throw them out and buy a new spindle. Not even HSD will repair them...so think about that next time you feel impatient.

[Hoytbasses]

Thanks to all who responded. 48 degrees isn't all that cold as compared to some of you, apparrently (without problems running parts) .

As I said: before , it was stuttering right after firing it up.... but after a period of time just running the router back and forth and up and down with the keypad.. (and after checking the proximity switches, and putting some mystery oil on the rails.....), the 0,0 function worked fine, the Z,0 function worked fine, so I ran a part.... it went very well, then 5 minutes into running the part, it stuttered again (and ruined about 50 bucks of primo walnut in the process).... It SEEMS that as it runs for a while the rail bearings loosen up with use....

In another thread, I read that pine dust really mungs up the bearing blocks.... and I had run about 30 plywood parts and even with dust collection there was a LOT of coniferous dust..... so I'm starting to think that maybe the bearing blocks are munged up with lots of pine dust..... so my next step will be to check and flush out the bearings if it appears they need it. Then try the whole thing again.

Thanks for the info on spindles, Brady but mine is a router machine. I don't think I've managed to toast the bearings on this machine. My former work (woodworking /guitar building teacher at a high school on cape cod) has a Desktop that has been used and abused by high school kids since 2013... never goes out of whack, runs like a top, rarely gets lubed, and runs like a tank. I baby my personal machine and it gets 'persnickety'... but I will prevail!


Thanks to all who responded!

Karl.

[bleeth]

Despite your appreciation of the Pats........
It may have nothing to do with the cold. Is this a dedicated computer or do you use it for other things as well?
You could be having issues with background programs and/or overloaded RAM.