Weight limits on Power Stick

[mike_boller]

Hello All,
My apologies if this information is in the forum but I've missed it. I'm a newbie with a PRSAlpha BT48 and the 8 foot power stick. Both the SB manuals and the forum threads suggest that you need to keep the weight down for the sake of the x-axis motor (with it being less of a problem for the alpha). While I realize that there is not maximum suggested weight, I'd like to know what range is acceptable and what is getting towards too heavy (deck and material total).

Thanks in advance.
Mike

[mikeacg]

Mike,

I was so excited when I bought my Buddy and the 12' PowerStick that I never asked those questions. I am learning the hard way that the extra weight can indeed cause problems. I am currently cutting tests for a 4' x 6' sign for a Kiwanis Park (and everyone and his brother that donated a penny wants their name on it) and the small letters at the bottom of the sign are giving me fits as the Buddy can't keep up with the movement required and I have 'o's that are not exactly round and 'w's that are pretty hard to read. An 8 foot stick might help this problem a little bit but I'll be real interested to see what kind of responses you get to this post.

Welcome aboard! You will learn a lot from everyone here! I got my Buddy in October of last year and this forum has been a godsend!!

Mike

[erik_f]

I don't know if this helps, but I'm sure if Dana gets his hands on the numbers he could pound out a reasonable idea for you. The standard generates between 60-80 lbs of linear force and the alpha is about double that. Here is where the math comes in and fine tuning of your ramping I would guess. I would think about it like this: If a man on a bike was coasting on a flat surface and the combined weight of the bike and rider were 300lbs how long would it take for 150lb weight to slow him down? The same idea would be applied in reverse for getting him back up to coasting speed again. My theory could be flawed but I figured I would through it out there...sorry can't help too much with the math

[mikeacg]

I'm thinking my problem might be deeper than previously thought. My Z is acting pretty sluggish at this point and even 'o's are not round. I'll search the forum but if anyone has any words of wisdom, please let me know!

Mike

[erik_f]

Sluggish in the z or in your x or both?

[mikeacg]

Erik,

Sluggish in the X only. I rotated part of the file to test it and now the o's are round but short. I thought weight might be an issue (since that was Mike's original question that got me thinking about it) but I took everything off the stick and still have the problem. It's like the X just can't keep up... I'm running tests right now to see if I can find a solution. I may try putting the aluminum table back on to see if that helps. It just started doing this lately so I'm hoping it is something easy (like cleaning the rack and pinion).

Sorry to hijack your thread Mike!!

[erik_f]

Are you losing steps in X? Maybe rollers are over tighten or some how became over tightened? What happens if you switch the x and y drivers (not actually switch them in the box just swap the wires) and drive the x with the y driver. This would give you an idea if the problem is after the control box. Before you take off your powerstick see if the powerstick moves freely with the motor disengaged from the rack.

[mike_boller]

No problem with the tangent... still, if anyone can advise me as to what is an acceptable weight range it will be much appreciated. I'm mulling over Erik's thought and planning on grabbing my old physics textbook from my office on Monday.

Mike

[mikeacg]

Erik,

Not losing any steps, just getting strange results. I switched materials, bits, etc. and still no results. Maybe one of my outfeed rollers is sticking! I'll check that next.

Mike,

Maybe when the ShopBot folks get back on Monday, we'll get some answers on weight. Have a great weekend!

[navigator7]

Mike Boller or MichaelSchnorr,
Did either of you resolve you issues on this?
I'm looking at the same machine and just asking questions.
Torn between the small foot print of the Buddy and a 96 x 60.

Michael Schnorr ...are you PRT or PRS?
Also...would slowing down your X travel rate fix the problem with heavy panels?