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  #31  
Old Sun 18 January 2009, 12:53
sailfl
Just call me: Nils #12
 
Winter Park, FL
United States of America
Wow, that looks like the dark ages of CNC.

Richard, you must be good to get any quality out of that.

What did they sell that for?
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  #32  
Old Sun 18 January 2009, 18:19
servant74
Just call me: Jack
 
Nashville (Tennessee)
United States of America
It looks like some of the first designs from ShopBot. ShopBot was initially designed as plans only what could be built from hardware store components, I was told.

Personally, I would like to see a copy of the 'initial plans' they sold way back when. It is obviously a lot less of a machine and probably $$ than a MechMate is today!
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  #33  
Old Sun 18 January 2009, 23:02
Cutter99
Just call me: Richard
 
On
Canada
Yes it was the dark ages...I started out with a kit I bought from them for a cable drive machine. I built a really solid steel table with outside dimensions of 6.5' x 13' long. It was not long before they offered rack & pinion and bigger motors. I used it to cut steel, aluminum, wood signs, plastic signs...I cut 10s of 1000's of letters out of pvc for the US Post Office. I drilled sheets for military products... I sold it in 2001 to a furniture maker and he cut tons of wood on it until a few years back he got into building luxury homes and mothballed the SB.

Over the period I used it I added a 5hp 600v Columbo spindle, 2 z's, Fog Buster misting system for cutting metals and spent soooo many hours tweaking, squaring, modding and upgrading. I redid the rails, tracks etc etc...

The 3 main problems I had were the ball screw z would loose its place, and the 1/2 or 1/4 micro stepping caused jaggies on the edges of certain parts of a circle. There were also real problems with files...weird cuts and movements that were not in the file.

SO a new controller would get me more power and resolution. That alone makes the machine much better than the last time I used it. IT will help with the cut quality, accuracy and speed. Less racking, and with more power to the Z it might hold its 0 better.

Next I will get new motors.

Then a new Z or 3. I read on a CNC site that 3 Z's will satisfy 99% of manufacturing needs, making a tool changer redundant.

Then the rails. I have a connection with a company that manufactures super high quality precision tubing for nuclear, underwater oil drilling etc. and they are really accurate. I may use this for the rails, as it will be free and I can get a 13' all one piece.

Yes a Mechmate is what I wanted the Shopbot to be back in 1996. I would like to rebuild my machine with a single y gantry beam.

RB

Last edited by Cutter99; Sun 18 January 2009 at 23:04..
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  #34  
Old Tue 20 January 2009, 12:57
jrabeneck
Just call me: Jimbo
 
AR
United States of America
I have a shopbot circa 1999 with exactly the motors that you have on your shopbot and mine looks almost exactly like the one that Gerald pictured in an earlier post. I recently purchased 4 Gecko 203v's and a pmdx 122 and mounted in the shopbot control box. The control box was a PRT 48x96 upgrade from the original PR96. I used the 44v power supply from the PRT box and wired the motors half step. Performance has increased dramatically.Jog speeds are comfortable in the 600-650 ipm range. It will jog faster but will sometimes lose steps. I am still using the original rails and rollers from the shopbot which lack rigidity. I have not done an a/b comparison on cut quality between the Gecko's and the shopbot controller but it seems that the Gecko's are very much smoother without the jerkiness.
BTW I am using Mach3.
JR
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  #35  
Old Tue 20 January 2009, 19:37
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Quote:
Originally Posted by jrabeneck View Post
. . . . . I used the 44v power supply from the PRT box and wired the motors half step. . . .
Thanks Jimbo. I think you meant half coil. You can go up to 75 Volts for the half-coil configuration which will cure the lost steps for jogging. (I think that Campbell runs his boxes on a low voltage as well?)
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  #36  
Old Tue 20 January 2009, 22:49
Cutter99
Just call me: Richard
 
On
Canada
Thanks jrabeneck.

What did you do with the Z? What speeds are you getting with the Z?

How did you find the learning curve of Mach 3?

That board is pretty cheap...

What did all the upgrading cost?

Anything else you can tell me?

Thanks,

RB
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  #37  
Old Wed 21 January 2009, 07:10
jrabeneck
Just call me: Jimbo
 
AR
United States of America
Gerald.
You are right. Half coil is what I meant. I will eventually upgrade the power supply to the higher voltage. The 44v power supply is working just fine for now.

RB,
I am still using the Shopbot Z axis. I have not had any trouble with binding. As for Z rapid speeds, I am using 50 ipm. It may go faster. I haven't tried. I an planning on upgrading the complete x y and z axis to the mechmate system as soon as I gather all of the parts .
The learning curve for Mach 3 is not any more difficult than for Shopbot. It is just different. G Code is not quite as easy to understand as shopbot language. I have found that it is easier to find post processors for Mach 3 than for Shopbot.
Costs for upgrading the control box:
4- Geckodrive 203v @ $147= $588
1- PMDX @$81
Assortment of hardware ( heatsink,resistors screws etc) ~$25
Total less than $700
JR
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  #38  
Old Wed 21 January 2009, 09:14
Cutter99
Just call me: Richard
 
On
Canada
How hard was it to get the proper settings in Mach?

Would you build your own or buy one if you could do it again?

50" per minute is pretty slow... I bet you could get it going faster than that.

I was thinking about welding the Z slide structure...

RB
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  #39  
Old Wed 21 January 2009, 10:37
jrabeneck
Just call me: Jimbo
 
AR
United States of America
RB,
If you know your VU (unit value)settings in Shopbot, it should be relatively easy to determine steps/ unit values in Mach 3. My original Shopbot VU for the x and y were 127.324. For the Mach 3 the values are 2546.48 or exactly 20X the original values. There is a calibration function in Mach 3 that will help determining the correct value.
If I had it to do all over again and I had money to burn I may have let someone else build the control box. Shopbot wants like $1000 to $1500 for the 4 gecko upgrade. That is about $300 to $800 more than I have invested. That $300 to $800 will go a long way towards rails and rollers and laser cut parts.
JR
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  #40  
Old Wed 21 January 2009, 13:18
Cutter99
Just call me: Richard
 
On
Canada
These are my motors:

Vextor PK296A1A-SG 3.6 / 5 degree Step / 2 Phase DC 1.5A 2.2Ohms
The Z motor is a PK268-02A 2A 2.25 Ohms
I was told they could be powered to 2.3A

How much juice can they take?
How many ounces would they be?
How would they compare to new motors?

Thanks,

RB
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  #41  
Old Thu 22 January 2009, 05:43
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
The PK296A1A-SG3.6 motors have 7.7mH inductance when wired half-coil, so they can handle over 80VDC. The Gecko's limit of 80V means that you'll get maximum advantage of those motors if you can wire them half-coil. (Some motors supplied to Shopbot only have four wires Black/Green Red/Blue. Those must be wired series.) The SG gearbox limits the torque, so half-coil connection is not a penalty.

The PK268-02AA motor is one of my favorite motors. I've installed dozens and dozens of them over the years in non-CNC projects, but they are small and not ideal for use on a large CNC router. I would not use a 23 frame size motor on a CNC router unless I were stranded on a deserted island and had no other motors available. The PK268-02A motors are rated 3.6mH half-coil or 14.4mH series. I use a 50VDC power supply when I connect that motor half-coil. If you used a 70V to 80V power supply, you would have to wire the motor using the series connection. Wiring the motor series would give you excellent torque, but it would also limit the speed to around 200 - 300 RPM. With a 5-tpi ball-screw, that would give you a maximum speed of about 1-ips.

Running two power supplies, a 70V for the PK296A1A-SG3.6 motors and a 50V for the PK268-02A motor is a possibility, but it would probably cost about the same to replace the PK268 motor with a PK296 motor. Even then, the problem is that a high-performance 34 size motor (motor with low inductance) works best when wired half-coil and a power supply in the 35-40V range.

Those PK296A1A motors just have the wrong inductance when compared to most other motors being used on a CNC router.
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  #42  
Old Sat 20 June 2009, 14:02
servant74
Just call me: Jack
 
Nashville (Tennessee)
United States of America
http://blog.makezine.com/archive/200...heir_code.html

Apparently ShopBot has open sourced their code. ... Interesting.

This happened some time ago, I guess I just missed it!
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  #43  
Old Sat 20 June 2009, 22:07
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Their input .sbp code (the stuff you see in the file with Notepad/wordpad etc.) has always been freely accessible and they promote it as better than g-code. This official "open source" announcement is just another push to get more recognition for their .sbp code, as opposed to g-code.

Their control software (actually firmware), serving a similar function to Mach3, LinuxEMC, etc., is definitely not open source

http://www.opensbp.com/

For people to use ShopBot machines they have to feed it a non-standard code (with .sbp extension). ShopBot is resisting a full swing to the internationally recognised g-code. (G-code is also very much "open-source", although their isn't an "official" site for it)
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  #44  
Old Sun 21 June 2009, 07:30
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
After visiting the OpenSBP web site, I fully agree with Gerald. The OpenSBP movement seems to be to "allow" anyone to use Shopbot "defined" instructions without worrying about getting a call from a lawyer for copyright infringement.

To RUN that code, you would still have to have a Shopbot controller. That code is not opensource.

I have written a lot of OpenSource code. OpenSource means that the source code, the actual code used to create the program, is included so that anyone can modify that code to allow the program to do whatever is desired. The only stipulation on OpenSource code is that it must remain OpenSource, meaning that if you modify my code and then pass that code on (sell or give) to someone else, you MUST include my source code and your source code.

Now, back to Shopbot. They have NOT released the code that they use to create the SB3 program; therefore, their code is not OpenSource. All they have done is to allow anyone to use their syntax and to encourage others to create tool pathing files using their code - so that they can sell more machines that use their proprietary controller hardware.

The OpenSBP "movement" seems totally self-serving to me. Frankly, I'm very disappointed with Shopbot for pretending that OpenSBP is something that it is not.
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  #45  
Old Sun 21 June 2009, 21:23
servant74
Just call me: Jack
 
Nashville (Tennessee)
United States of America
Now we just wait for a nice geek to do a SB to G-Code converter!

If someone did and got it really working, at least SB couldn't complain that they are ripping off SB code!

Still, nothing to lose sleep over at this point, one way or the other.
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  #46  
Old Mon 22 June 2009, 00:50
Alan_c
Just call me: Alan (#11)
 
Grabouw (Western Cape)
South Africa
Send a message via Skype™ to Alan_c
Shopbot actualy released one, I have a copy but cant seem to find it on their web page right now, go there and do a search.
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  #47  
Old Mon 22 June 2009, 04:21
jrabeneck
Just call me: Jimbo
 
AR
United States of America
UX_SBP.exe. It is a utility included with their control software.
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