Artcam Pro-tool definition override SB settings?

[imacarver]

I am a new Shopbotter and I am wondering if anyone has been able to control feedrates and spindle speeds with the user-defined settings in the Artcam Pro tool library? Or does everything need to be reentered into the Shopbot as tool variables? I also have a Shopbot equipped with an ATC, which may complicate the matters.

[richards]

I don't have Artcam Pro, but I use its weaker sibling, PartWizard II. The feed speeds defined in the tool library are automatically inserted into the tool path (SBP file). When I want to disregard those speed settings and use manual speed settings, I edit the SBP file, do a search for lines containing "MS," and then turn the "MS," into a comment " ' MS," by adding a single quote character ( ' ) as the first character in the line.

[paco]

Yes, feed rate is automatically entered from the post. What kind of problem are you experience exactly about the feed rate?

As for the RPM, if you want to control it from the code, you need something that will send some signal (value) to the VFD and I'm not sure what it would be since SB3 only output low/high signal. I do know how to have the spindle RPM output from the post but how would this value be sent to the VFD/spindle assembly? Maybe I don't know of some connection that can be made from the controller board... or maybe the VFD can understand some kind of morse code from an output signal!?!?!?

[bhalle]

I am by no means any expert having had my ATC only a couple of weeks now but I can tell you that the way speed information is passed from Artcam Pro is by way of the tool number. The actual RPM information is not used by SB3.

When you set up tool paths in Artcam, the tool you select should have a tool number specified (1-6, corresponding to the tools in the ATC tool holders). In SB3, it uses this tool number to set the speed of the spindle ... basically as part of the tool change operation it sets a 3-bit value which is sent to the VFD which corresponds to a speed setting register in the VFD. The speed setting register contains a multiplier value which results in a specific RPM.

So, at least in my setup, if you want to change the spindle speed for a specific tool, you have to modify one of the ATC files to set the proper 3-bit value for the corresponding tool number change. This means that if you load up a new bit into a tool holder, you need to adjust the speed value for that new tool.

I don't remember off the top of my head which file it is, but I can track it down if you need it.

[paco]

How are the VFD and the controller box interconnected? Output signal from SB3?

What is an ATC file; is it a sbp file (routine)?

So we could say that the ATC you have have a 6 increments automatic speed (RPM) control... right? Beyond that, it involve changes.

Maybe SB3 doesn't handle RPM values (specific ones) but I believe some other controller do 'cause there's an [S] value available in the post (most common ones) corresponding to the exact value set for each tool bits of the tool data base. I use this in my post to have an RPM display at the start of each file so I can set my RPM from what I've took note of in my tool data base.

Is it right to say that the largest expense regarding the ATC is actually the spindle itself?... maybe the cones next... then the holders... not that one can do it without one of 'em...

How is your Z zeroed, fixed zeroing plate or indexed tool?... or else...

[imacarver]

Brett, you are correct. That is what I would like to change. In other CAD/CAM programs you can specify a given spindle speed for each toolpath, with Shopbots setup you cannot do that without using two different tool numbers, which means I need duplicate tools. I don't understand why the Shopbot cannot read the spindle speed values through Artcam?? It seems like they missed a point.

[bhalle]

Paco,

The VFD and controller box are interconnected via output signals from SB3.

The ATC files I am referring to are sbp files ... there are a set of them that come with the ATC and handle configuration, calibration, zeroing, tool changing, etc.

With the 3-bit value, I guess it's really 7 possible speeds. They aren't so much increments as mappings to speed registers in the VFD. You have to manually set up the speed registers (which are multiplier values to get to the actual spindle RPM).

I would guess that since there is this "relationship" between the speed code (the 3-bit value) and the VFD registers that there is no way to relate the RPM value from SB3 without knowing all the intervening information -- in other words, no general purpose mechanism to handle it.

Yes, the ATC spindle is BY FAR the most expensive part of the package. I expect the VFD is next.

Z-zeroing is done the standard way using the z-zero plate on the material.

There is, however, a fixed zeroing plate used to determine the individual tool's "length". There is a calibration step to run whenever you load up a tool holder with a new bit -- it references off the fixed plate.

[bhalle]

Mike,

I agree that the speed setting appears to be a weak link in their implementation. The challenge, I imagine, is that the connection between the controller and the VFD is limited to the 3-bit register number mapping. Given that they don't know what the registers are set to (and what the multiplier is to get to the actual RPM) that it's very difficult to directly map the RPM value from Artcam to a speed setting.

I expect, however, that this will improve as we all get more experience using the ATC. I can already see possible improvements to the software and the integration.

[paco]

If SB3 could have some kind of feedback from VFD RPM, maybe two output signal could increment (up or down) the RPM... but I understand that it's a little more complicated than I first thought since two controller (SB3 and VFD) must speak the same... but since it's the VFD that govern the spindle RPM, maybe it could be calibrate from the bit registration you mentioned than controlled (increment) with output signal; like one signal(blink)=250 RPM up or down, two signal(blink-blink)=two increment of 250 RPM...
Can the VFD receive such signal to increment the RPM speed? Say if you have a remote on which you push + or -? Such circuit (SB3 output to VFD input) shouldn't be so complicated to build...

[richards]

The VFDs that I've studied normally use an analog input to allow spindle speed to be changed on-the-fly. Using a digital output from the Shopbot controller board would be difficult, since other circuitry would have to be designed to bridge the digital to analog gap. A pulse train, similar to what Paco described is often used. The digital output is pulsed a certain number of times and another circuit counts those pulses and converts them into an analog voltage. The VFD receives the analog voltage and modifies the spindle speed. The drawback to all of this is that it takes a finite amount of time to send those pulses. Normally you wouldn't send those pulses during a move meaning that spindle speeds wouldn't follow the cut's ramping speeds.

[bhalle]

Paco, Mike,

For the ATC spindle, you can change speeds from within an sbp file -- you are limited, though, to setting a 3-bit pattern which maps to speed registers set in the VFD. So, as long as you know what a given register setting will correspond to RPM wise, changing bit speeds isn't an issue.

The specific challenge given the implementation ShopBot has provided at this point is figuring out how to map an RPM value specified in Artcam to this speed changing capability. The RPM's don't necessarily match exactly.

With a little bit of software work, I can see how one could get a reasonably close solution.