Retrofitted CNC Mill

[DanThomson]

Ok, I know this might be a long shot and I apologize in advance if I am posting this in the wrong section.

I recently added a retrofitted CNC Alliant(Bridgeport clone) mill to my shop.
The retrofit kit is made by CNCMAsters, I picked it up used on Craigslist and while the controller isn't the most current one available, I think it will work well enough for me.

Now onto the question...
I began experimenting doing some actual cuts today and am finding that the machine is cutting groups of straight lines instead of smooth arcs and/or circles.
The toolpaths were created in RhinoCam and then fed to the CNCMaster's "Master" software.

Does anyone here have any experience running CNC mills from RhinoCam?
When I contacted the company for tech support all they want to do is sell me the most current controller and software package.

I have attached an example of the G code,
Any advice, help, comments are most appreciated!

[myxpykalix]

I don't know rhino or these machines but your description of "the machine is cutting groups of straight lines instead of smooth arcs and/or circles."
tells me that whatever pgm you use to make your designs you have to hilite your lines and convert them to "bezier curves". That should make the lines smoother.

[steve_g]

Possibly your geometry is nothing but line segments... you may need to join them. This seems to happen a lot when exporting and importing dxf files.

SG

[dana_swift]

Dan- your test file contains no arc commands. Just a list of Jog (g00) and linear cuts (g01).

Your post processor must not be set up for your controller.

My suggestion is hand code a simple circle cut in a G code file and run it. See if the controller does what it is supposed to. Then use the manual for your controller and test each supported G code operation. That will check out the controller/mill setup.

Then concentrate on the post processor setup. Possibly consider using Vectric products (other than partworks) to generate your cut operations. Vectric supplies very good post processors for a huge list of machines including ones that are not G code driven. Then they provide an excellent manual on how to write/configure your own PP to meet your needs. Then you can use the same program for both your bot and your mill. Just select bits definitions appropriate to the material and the correct PP.

There are other users on the forum who use RhinoCam and may be able to consult on the PP setup for them.

Good luck, I am interested in adding a CNC drive to a Bridgeport knee mill, so I am interested in the CNC retrofits for them. The ability to cut steel is something I am quite interested in, and your experience with the CNCMasters may be interesting, although their attitude about support is light years away from SB.

I suspect others on here would love to cut steel also.

Good luck- keep us posted.

D

[dana_swift]

I just went and spent some time on the CNCMasters web site, which got me thinking.. does ShopBot still offer "motion control systems", to allow driving the Bridgeport mill with Alpha-servo drivers? Then I could use shopbot control code on either machine.

Does anybody have experience with hooking shopbot motion controls to a Bridgeport? Does SB still offer the motion control product for sale?

Musing..

D

[DanThomson]

First off thank you everyone for the responses!

Dana,
According to the CNCMasters web site and manual,
The Master Software supports these standard G-Codes and M-codes:

G00 = Position (Fast speed)
G01 = Linear interpolation (Feed speed)
G02 = Circular interpolation (CW)
G03 = Circular Counter-clockwise interpolation (CCW)
Format: X__Y__I__J__ I,J are relative distance from start to center. Incremental Z can be added for helical designs.
G17 = Cancels G60 Command
G40 = Cancels G41 and/or G42
G41 = Tool Radius compensation left
G42 = Tool Radius compensation right
G60 = Switch data from Y to W * radius factor
G70 = Input in inches
G71 = Input in millimeters
G73 = High-Speed Peck Drilling Cycle
G81 = Drilling Cycle
G82 = Counter Boring Cycle
G80 = Cancel Cycle
G83 = Deep Hole Peck Drilling Cycle
G90 = Absolute move (Modal)
G91 = Relative/Incremental move (Modal)

M00 = Pause
M03 = Spindle on
M04 = Spindle on reverse
M05 = Spindle off
M08 = Coolant on
M09 = Coolant off
M30 = End program

I do now see that my example g-code contains no arc commands (G02,G03)
So now the question is, why is RhinoCam not outputting theses toolpaths as arcs?

I also noticed that RhinoCam is also showing some of the toolpaths as straight lines instead of arcs.
I have attached the view of toolpaths from a Profiling Operation as well as a Pocketing Operation. You can see that in the Profiling Operation the toolpath is circular as it should be, however the Pocketing Operation has a jagged, straight line toolpath.

I have also attached the specifics for my post processor.
This post processor is what is supplied from CNCMasters to be used in RhinoCam.

At this time I am clueless to why RhinoCam is not including the arc commands in g-code??

[Dusty Knobel]

Dan,
I draw in Rhino 4.0, but use Vector for toopathing not RhinoCam. A quick research shows RhinoCam as a descendant of VisualMill. In this webarticle is a description of how to set the postprocessor in VisualMill http://www.k2cnc.com/2009/09_Support_Mach2_Mach3_Setup.asp#Mach_3_Smoth_Arcs _Circels
Don't know if helpful; or not.

Dusty

[DanThomson]

Thanks for the link Dusty,
however I previously tried changing the settings that article suggests with no changes or success.

[Brady Watson]

Does anybody have experience with hooking shopbot motion controls to a Bridgeport? Does SB still offer the motion control product for sale?



Yes. I have an Alpha powered Bridgeport BOSS 5 that I retrofitted to run under SB control. It could also be done with Geckos or other S&D drivers + a developer board or 4G board to run SB3 on the mill using the original steppers or servos. I'd post a pic...but it is wrapped up right now waiting for the riggers to bring it down.

-B