Couple questions on the ShopBot Link

[Keith Larrett]

I'm relatively new to the world of CNC. I'm using eCabinets and the ShopBot Link. When I first got my ShopBot one of the forum members, Tim Lucas, very kindly came over to my shop for the day and helped me get started on the set up. He also shared some settings for the ShopBot Link to get me going.

Since then I've been spending time getting to know my machine and what it is capable of, experimenting with feed rates, spindle rpm, different depth passes etc. I'm primarily cutting sheet goods, 3/4" plywood and MDF. I'm using a 3/8" compression bit and have set up the ShopBot Link to cut in one pass leaving a skin of 0.03 with a climb cut and then do a conventional cut final pass on the line.

The problem is that on the final pass it slows down considerably. I have the "% Full Feed for Through Cuts" set to 100%, but it still slows down a lot on the final pass. On the SB control software it is showing the feed rate at 2 ips (or 120 ipm). This matches the setting I have for "Min Feed Rate" so I suspect that is the problem. I'm hesitant to change this as I'd don't know if the "Min Feed Rate" just affects the outline tool, or if it affects all the tools. I don't want to set to high a feed rate for the smaller bits.

Any advice would be much appreciated. Actually if there is anything else that I should change in the rest of my settings I'm open to any suggestions. I'm probably erring on the side of caution with a lot of my feed rates. The machine doesn't sound or feel like it is straining at all so I'm sure I could probably bump them up some more without compromising on cut quality or accuracy.

My second question is regarding setting the z-axis. Is it possible to zero the tool to the spoil board using the ShopBot Link? Today I cut a project that had three different thickness of plywood/mdf. If I were able to zero to the spoil board then I would not need to zero the tool after each sheet change.

I have a 60x96 PRSalpha with ATC and 16.9hp Regenerative Blower.

Thanks in advance for any help!

[Justin G]

Hi Keith, welcome to the forum and the world of shopbot. I'm also a new guy here and am looking at purchasing the link in the near future for cabinetry applications. I'm currently about 50% through the Ecabs online training.

Although I cannot speak to the link or how to use Ecabs, Inside the actual shopbot control software you can increase your cut speed on the fly during a part file by using the "shift" and " > " keys. Same for slowing it down with "<" key. I do not have an ATC, but this could work temporarily until you sort out the programming. It only controls X/Y speeds and not Z though. Certainly try this during an air cut just to be safe. Not sure if it will help but something good to know regardless. This really helped me dial in my speeds & feeds when learning the machine.

[Keith Larrett]

Inside the actual shopbot control software you can increase your cut speed on the fly during a part file by using the "shift" and " > " keys. Same for slowing it down with "<" key.

Thanks Justin! I had read about changing the speed mid cut, just didn't know how to do it. Now that I know the keyboard shortcut I will try it out. It's like a gas pedal for my Bot

[Justin G]

No problem. Here is the link to the shortcuts. Although for spindle speed mid-cut, I can't use the keyboard. I have to alt+ tab out of the control software and click on the spindle speed control box and type In new speed and hit enter.

http://www.shopbottools.com/mTechSho...0Shortcuts.pdf

[Tim Lucas]

Hi Keith,

I hope to have time to try out a couple ideas on the speed change & zero questions if you have not already solved it.

Tim

[Keith Larrett]

Thanks Tim. I'm still working on it.

[Gary Campbell]

Keith...
Set your "Max Feed Size" from 1000sqin to somewhere between 100-150sqin.

[Keith Larrett]

Set your "Max Feed Size" from 1000sqin to somewhere between 100-150sqin.

Ok. That makes sense. Thank you Gary. I checked in the manual and, if I understand this correctly, if I set the "Max Feed Size" to 150sqin then any part greater than that will be cut at the % specified in "% Full Feed in Through Cuts" and any part less than 150sqin will be cut at the speed set in "Min Feed Rate".

Is that right?

[Justin G]

That completely makes sense if that's right. I'm highly considering getting the link in the near future and this kind of stuff helps a great deal. Another win for the forums (and Gary).

[Gary Campbell]

Keith...
The way I understand it is that all pieces at the "Max Feed Size" and above will cut at the bits (max) feed rate * the percentage. (I always use 100) Below that they cut proportionally lower. Half the square inches, half the speed. Nothing will cut slower than the min feed rate.