G0704 CNC AC Servo Rebuild (Picture Heavy)

[macardoso]

Its been quite a while without an update here!

I spent a good two weeks trying to identify an issue which would cause my machine to move unexpectedly and violently every time I enabled the motors, tried to home the machine, or jogged in any way. After recording a ton of data and presenting it to Warp9TD, we were able to find that the was an anomaly in their code/interface with Mach 4. Andy was extremely helpful and they were able to correct the issue immediately in the next release of the plugin. Everything seems to be working great now!

I wanted to try out the machine with the latest features I added. To do this, I drew up a slightly complicated part up in Inventor. Rough size is 4x2x1".



This was programmed in MasterCam. There were 9 tools used in 10 operations.

1. 3/4" endmill used to face the part
2. 3/8" ALU-Power endmill: Dynamic roughing and island facing
3. #3 Spot drill to spot the 6 drilled holes
4. 1/2" endmill to drill the 4 large holes. This was the first time I used the chip break canned cycle. It worked great!
5. 3/8" endmill to drill the smaller holes. Also used a chip break canned cycle
6. 5/32 endmill to clean up what the 3/8" endmill left behind. I used a dynamic rest machining operation which was very efficient. This tool also did a contour to finish the walls of the cylindrical bosses.
7. 1/4" endmill to rest machine the lower profile (too deep for the 5/32) and finish.
8. 3/8" ALU-Power endmill again to do a helical bore on the larger center bore.
9. 1/4" ball endmill to finish the central boss inner wall and cut the 1/8" radius on the floor
10. 1/4" Chamfer endmill to cut a 0.020" chamfer on all edges

All the tools were preset in Tormach Tooling System (TTS) compatible holders and loaded into the Mach 4 tool table.



Here is OP6 rest machining shown in MasterCam.


Here are a few pictures of the process. I also have a couple of short videos if anyone is interested. I can't seem to post anything longer than 18 seconds so it is rather limited. If you could tell me how I'd really appreciate it.





And the finished part right off the machine. Material was solid PVC. Tool marks are super visible because it is dark plastic, but the surfaces are very smooth. If I were to run this part again, I would tweak a few things to make it more efficient and to avoid a few blemishes where the dynamic roughing marks were never cleaned up by the finish passes.



After having so much fun working on this part, I decided to really test myself and design a backside to the part. This will require machining of soft jaws (which I have never done before). The "fence" around the part is 0.5" tall with a 5 degree taper on the walls. The cavities in the part are setup to be machinable with the 5/32 cutter and are 0.2" deep into the 0.25" thick lower rim.

I already own a HSS 5 degree cutter so it should be good practice to program a tapered cut. The hardest part will be keeping everything aligned such that the through holes line up with the edge of the tapered web.



Will keep everyone updated with how this adventure goes.

 

[Boswell]

Your work encourages me to look into Mach4 again.

 

[macardoso]

Looking for advice and feeback from anyone with soft jaw experience...

I used Inventor to take a model of my vise with the soft jaws installed and the part I want to machine. I used a subtract boolean function to cut away the soft jaws wherever the part was. I then cleaned up the cut by removing material wherever I didn't want it to touch the part. I also added 5 thou of clearance on all of the walls to prevent the part from needing to be jammed into the fixture.

Both parts, before subtraction



After Boolean operation



After cleaning it up. Blue is for contrast...



Part depth is set by the top shelf. The bottom of the part does not touch the jaws. Total depth gripped is 0.15"



Any curves beyond 180 degrees were trimmed to prevent the jaws marring the part when opening. 5 Thou of clearance is visible around the part.



Does it look like I am on the right track?

 

[macardoso]

Your work encourages me to look into Mach4 again.

I love the program. Hated it at first (was such a Mach 3 fanboy)... but I think it is decades ahead of where Mach 3 got to. I have been able to add anything I could dream up using the LUA scripting.

Would be happy to help if you need it.

 

[Boswell]

I may be reaching out. I did a little bit of coding in LUA sometime last year so I have a head start on that aspect. Really the thing that is holding me back is that Mach3 is meeting my needs and I am hesitant to fix something that is not broke. I also have a Mach3 GUI that I really like and have gotten used to. Anyway having said all that I like the idea of being able to use LUA when needed and take advantage of the other improvements. We will see. Might be a Christmas break project.

 

[macardoso]

We will see. Might be a Christmas break project.

Hit me up. If you take the plunge, I don't think you'll regret it.

Edit: You can also keep Mach 3 set up on the same computer so you can always go back to it. I did that while I was originally setting up Mach 4.

 

[bakrch]

Looking for advice and feeback from anyone with soft jaw experience...

I used Inventor to take a model of my vise with the soft jaws installed and the part I want to machine. I used a subtract boolean function to cut away the soft jaws wherever the part was. I then cleaned up the cut by removing material wherever I didn't want it to touch the part. I also added 5 thou of clearance on all of the walls to prevent the part from needing to be jammed into the fixture.

Both parts, before subtraction

View attachment 307464

After Boolean operation

View attachment 307465

After cleaning it up. Blue is for contrast...

View attachment 307466

Part depth is set by the top shelf. The bottom of the part does not touch the jaws. Total depth gripped is 0.15"

View attachment 307467

Any curves beyond 180 degrees were trimmed to prevent the jaws marring the part when opening. 5 Thou of clearance is visible around the part.

View attachment 307468

Does it look like I am on the right track?

Looks good to me. My only concern is that I do not know how slippery PVC will be in the jaws. It should be okay if you keep everything dry and degreased, but I've launched a few plastic parts out of soft jaws in my day when holding this shallow.

 

[macardoso]

Looks good to me. My only concern is that I do not know how slippery PVC will be in the jaws. It should be okay if you keep everything dry and degreased, but I've launched a few plastic parts out of soft jaws in my day when holding this shallow.

That's what I'm worried about.... I may redesign the jaws to be closer together. Can't put the part deeper if I want to add a chamfer around the part...

 

[Boswell]

how about doing it in two operations. First is to mill out one of the thru holes. Then use the through hole to secure the part.

 

[macardoso]

how about doing it in two operations. First is to mill out one of the thru holes. Then use the through hole to secure the part.

That's not a bad idea. Unfortunately, I would need to rough out almost all the material to access those holes. By that point, all the heavy machining that could possibly throw the part would be done.