Breathing New Life Back Into a Shopbot PRT 48 X 96 CNC Router

[Helicopterjohn]

Hi,

I recently purchased a used Shopbot PRT 48 X 96 CNC Router.  The previous owner had modified the unit to work with Mach 3 software.  It had Gekco 202 geckodrive step motor drives.   They were a little noisy, especially when running at lower speeds.  It originally had a CNC4PC breakout board which successfully operated the Shopbot.

I cut a lot of plastics and had the need to reduce the spindle RPM in cutting this material.  Being new to the DYI concept of CNC tools I did quite a bit of research on possible retrofits to bring new life back to this machine on various forums on the internet.

I decided to install a Super PID Speed control kit on the router with a minimum RPM of 5000 and still have good torque for cutting.  I also decided to remove the current Shopbot control and make my own DYI control.  The only remaining electronic items left were a couple of proximity switches and the Stepper motors.

I also installed the 2010 Screen Set for my Mach 3 software that is feature rich in that it allows you to do semiautomatic tool changes, probing etc.

Yesterday a friend in Florida helped me assemble and wire up all the electronic components.   I couldn't have done this without his help.  I used a PMDX-126 Multi-Mode Breakout Board, 2 each PMDX-133 Motherboards for mounting the new Gekco 203V geckodrive step motor drives, and a PMDX-107 isolated speed control which interfaced with the Super PID Speed controller.  This allows me to have spindle RPM control via GCode that is run in the Mach 3 software.  Using the 2 each PMDX-133 motherboards will allow me to use up to 6 drives.  I also have 2 parallel ports one in the main CPU of my PC and also an add-on parallel port card in case I need any additional inputs etc. in the future.  I hope to add a 4th axis sometime in the future.

I now have to install the components in a cabinet that my brother made for me and install appropriate cooling fans for the electronics.

The Shopbot now runs like a dream.  QUIET and SMOOTH.  The total cost for the retrofit was around $1500.00.  All new electronics except for the stepper motors and a proximity switches.

John
 

[Tweakie.CNC]

Sound like a good job done John.

Tweakie.

[Helicopterjohn]

Yes,  It feels good to have it running as it should.  The Super PID Speed Controller and the 2010 Screen Set with Semi-Automatic Tool Changer and Probing options make it a really nice tool.

John

[Hood]

Wheres the pics
Hood

[Helicopterjohn]

Hi Hood,

First, thanks for your interest.

I currently just have it bread boarded.  i.e. wires everywhere  Ha Ha    I am working on installing the components in a cabinet.  I also need to order some heat sink material that I will mount the Gekco drives on.  When I get it finished I will post some pictures and a link to a video.

John
 

[Hood]

Look forward to it
Hood

[Helicopterjohn]

Hi,

I made some revisions to the component locations in the drawer.

I did some machine work on the front panel, i.e. recess for mounting ON/OFF switch, pocket for mounting the Super PID LED RPM Display, and air intake holes.

The PMDX-133 Motherboards with associated Gecko203V's have been mounted along with the cooling fans.

The wiring has been cleaned up for those components and the connections to the DB9 connectors for the motor drives.

I finally got the additional DB9 connectors to finish the project and will clean up the other wiring and install the remaining DB9 connectors on the back of the cabinet.

I should also get the additional power supply that will run the cooling and exhaust fans for the electronic components within the next couple of days and finish that wiring.

I guess the heat sinks and the cooling fans were probably overkill as the Gekco203V's now run at room temperature as well as the Shopbot Router motors.

I now have one cool/smooth running Shopbot with many thanks to my Florida Friend.

John

[Hood]

Looks great
Hood

[Helicopterjohn]

Hi,

I Installed the rest of the DB9 Connectors yesterday and tested the Shopbot for proper operation and all is well.

I also need to add my second parallel port via a PCI card.  I intend to operate both my vacuum pump and dust collector via solid state relays that are actuated via MCodes. These solid state relays will be hooked up to my PMDX-126 Break Out Board.  These will also be able to be operated via buttons on my Mach3 2010 Screenset.

John

[tripleblack]

i had a shopbot prt 48 x 96 . bought it in 1998. was the cable drive. changed to rack and pinion drive with geckos after a few years. software was easy to use . but the controller would poop out and lose connection frequently. switched to mach in 2008 and was pleased to note  a difference in motor smoothness.