Alpha Vs Standard - recommendations needed

[foamman]

Hello,
I have a PRS standard which I have been using for the last 4 years with a certain degree of success but also frustration. The tool frequently looses XY or Z position and proceeds to ruin what ever part I am cutting. I have done all the fixes recommended by ShopBot (new computer, no internet, no upgrades, grounded, slower cutting speeds, etc) but it still happens enough to be fairly frustrating.

I am considering upgrading to an Alpha and would like to hear advice from anyone who has experience or knowledge of going from Standard to Alpha. Especially if you have had similar problems. Can anyone speak to whether the closed loop of the Alpha motors and controls will help keep the tool located at the spot it is supposed to be?

I guess I would like some advice/recommendations before making another large financial investment into my ShopBot.

Thank you for you time,

Ben

[jerry_stanek]

I also have the standard and I haven't had any problem loosing steps. I cut all kinds of material and I sometimes I push it hard. The only time I have lost steps is when I make a mistake and try to run it at speeds that are above 8 IPS. I can surface at 8.5 IPS but that is all.

[cowboy1296]

I have a buddy standard. i use to loose comm a lot loosing my x, y, z. to my understanding there are still a lot of things running on your computer (services) that interfere with the shopbot. more then you listed above. i am no means a computer guru but some on here are and they suggested following the advise on this link to set yourself up with bare bones. http://www.blkviper.com/WinXP/servicecfg.htm
if you will scroll down this link/page you will find a chart with bare bones off to the right.

this is for windows xp, if you are running 7 then there is another setting for that.

another mistake i made was to try and run a file from a flash disk. i now know to transfer the file to the control computer and then run it from the computer.

another mistake i made was thinking that my usb ports were fast enough. after my hub died on me i just plugged straight into control computer. i finally bought me a new hub and i think that helped also.

after following their advise my shopbot has run at least 95% better

hopefully one of my mistakes and learning can help you.

[gerryv]

Ben,

From anything I've read over the last few years my vote would be that this is NOT a Standard vs. Alpha issue.

On the other hand there has been much discussion involving this and similar comm type issues. I can't offer advise but two discussions that stood out were (1) a fairly recent one where the fellow took a "less is more" approach to grounding and routed his ground somewhat differently which worked for him, and (2) a discussion earlier this year where the fellow discovered that his Z-Zero plate was rattling about causing randomly occurring data signal noise that in turn caused comm. issues. He affixed (and maybe grounded or ungrounded it) in a way that eliminated his problems. These were two strategies that seemed to do the trick when the more common efforts at better grounding didn't work.

Maybe you can find these threads or maybe these fellows will notice and offer more experienced advise.

[gene]

Hi
I have a alpha and the reason i purchased it over the prt was that if the bot lost steps then it would stop. at the time it was the first cnc that i had purchased and i was totally green at cnc operations. the last thing i needed was a cnc that could possibly loose steps and keep on cutting. i would not know if it were something that i did wrong or the cnc loosing steps. it was my understanding that the feedback from the motors ( closed loop) was the difference between the two, plus the higher speeds on the alpha. Please tell me if i have this correct. i surface my top at 12ips at .03 depth. Thanks Gene

[gerryv]

Gene makes a good point. If lost steps IS the cause, then the alpha would be an advantage it would seem. That said, and again from being a daily reader of the forum, the standard Shopbots don't seem to have much trouble with lost steps -unless pushed really hard. Best you consider input from some of the fellas more knowledgeable than me though.

[curtiss]

Have you tried to isolate the problem and make sure it is not coming from your dust collection system / grounding ??

I used some rock salt around a copper rod for my ground that is directly outside the shop wall. It is suppose to consume the rod faster but such is that for a better ground.

[shoeshine]

I would echo the sentiment, I am only 2 years on my PRS 48BT Standard, but the only time I lost XY was issues with my comp. Services running in the background etc...
(I have run some pretty extreme scenarios too, cutting brass and all)

make sure all the bases are covered... comp, USB, comm speed, grounding, etc.. before making that investment.

Chris

[adrianm]

I cut 18mm MDF sheets pretty much all day and you can't get much worse than that for creating static electricity.

I've never had any issues with lost comms etc and my grounding is a copper wire from a leg bolt on the Shopbot running directly to a 4ft copper rod in the ground outside the workshop.

I used to have a ground in the dust hose as well but when I changed to a different hose I never reconnected it and, as there weren't any problems, I've never bothered.

[russ]

http://www.talkshopbot.com/forum/showthread.php?t=12954&highlight=gecko+drive+standard

[michael_schwartz]

Does your standard have the new control box, and motors or is it the older style? If I remember correctly they upgraded the motors, and controllers around 2009 or so.

How exactly do you define loosing position? What sorts of materials are you cutting, with what tooling, and feed rates?

From my experience lost com seems to be either a PC issue, USB problem, or Static. Regarding static certain materials are worse. Does this happen more with MDF for example compared to solid wood? This could be a grounding issue, but if you have tried to address that based on the advice from Shopbot or others here than maybe there is another explanation.

I have had my standard loose steps on occasion when pushing the limit on cut speeds.

I would check and make sure your not grounding static from the dust shoe or hose to the machine. After replacing my dust hose I tried cutting some MDF without reconnecting my ground and sure enough I started having com errors. I hadn't run my ground yet because I wan't having problems when cutting solid wood. Make sure the Z zero plate, and clip are isolated as well.

If you can afford upgrading to an alpha that would probably be a wise decision depending on the work that your doing.
I plan to do the same eventually. You can probably sell your old motors, and control box pretty easily. A standard should be pretty reliable though. Mine has been and seems to get the job done.