PM45 CNC Mill, BobCAD/CAM -And No Time To Sleep!

Ray C

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Oh brother, this is addictive! I'm still deeply in learning mode but there's light at the end of the tunnel. Here's a quick rundown.

The machine itself setup with no physical problems at all but the initial software and driver configuration was tricky. The manual I wrote (and thanks to user Boswell for proofreading it) should make life easier for future generations.

It took about 2 days of reading/reviewing Mach 3 videos and manuals and another 8 hours of hands on tinkering to get comfortable with controlling the machine through controller software only.

It took a solid 2 days of reading/reviewing the BobCAD/CAM software to design a tool path that made sense according to my prior knowledge of manual mill operation.

The results so far are great. This opens the doors to endless possibilities. For now, I'm making the same part over and over to improve both milling time and final finish. Honestly, I have no idea how someone could jump into CNC without first using a manual mill. Anyhow, looking back, it took about 4 days of upfront work before I felt comfortable enough to go cut metal. I pains me to say this but, that machine and software can do better work than me... and I've got more than a few hours of time with my hands on a manual mill.

Here's a couple parts:

This is 1045 at Rockwell 38. It's the same pattern cut on top and bottom. Top one was an optimized toolpath that I tweaked. Bottom one was cut with the defaults that the BobCAM came up with. Bottom one is not to "spec", top one is dead on. Tweaking is done by changing the entry methods and feeds/speeds. (More on that later). It only needs deburring and I'm now ready to use the software to break all the corners for me but, the one point bit I have is too large for this part so it will have to wait.

Steel Part.JPG

Here's a pic of the same part in AL. Easy... like taking candy away from a baby.


ALpart.JPG

At first, the parts were coming out slightly oversized by about 1-2 thou. I thought it was backlash problems and I did some adjustments to no avail. Duh... I was using a brand new endmill and assumed it was 0.375 -not... it was 0.07425. In software, I did a compensation for 0.00075 and bingo, parts are dead on (checking with mics, not calipers).

Software: I agonized for weeks (if not months) over which package. I ended-up with BobCad/CAM 4 Axis Mill Standard -and two days later upgraded and purchased the Professional toolpaths for 3 Axis advanced milling. I haven't used it yet. Everything shown is only done using the Stadard package.

I was really on the fence about which package but after really digging in, it seemed that BobCAM was the way to go. I'm not crazy about the CAD aspect of it but, I use Geomagic for CAD. Geomagic CAD has very high-end features for creating BOMs etc and I also prefer parametric CAD. CAM-wise, BobCAM is doing the trick. The salesman I had (Eddie Osborne) really did a great job of negotiating price -and a previous salesperson I spoke to didn't come close. If you go with BobCAM, give this guy a call you can ask for him by name. It might help if you mention you came from this website. This salesman also tossed in some freeby packages. One will let you scan something and you can convert it to 3D then mill it. It will be a while before I can get around to that.

Interesting thing I learned... Of all the major CAM software packages out there, many of them purchase/license the toolpaths from the same company. The vendor you buy from just has their own GUI wrapped around the 3rd party toolpath software. -Found that interesting. When I found this out, my focus shifted about how I analyzed the packages and start to focus more on the look & feel and how their pricing was setup to make it equitable for me. I liked the way BobCAD had a wizard that walks you through a sequence to make the basic part then, you can optionally go back and tweak the parameters. I also like how you can mix & match toolpaths from other products in their portfolio -and I really like the fact they don't have an annual maintenance fee. So far, it hasn't crashed and I haven't seen any bugs yet.

Anyhow, I've been really busy with this and haven't contributed much here lately... Also, in the last week I did a spring cleaning on the entire shop. Scrubbed the floors and did detailed cleaning on all the heavy machines. -Big job. Got it all done in 3 days.

FWIW: A couple people have asked if I'm selling my old PM45... The answer is no. It's 5 years old now and still tight as a drum.

OldPM45.JPGKeyboard Table.JPG

Steel Part.JPG ALpart.JPG OldPM45.JPG Keyboard Table.JPG
 
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The software is what I am working on now. CAD and CAM. I am watching the videos jumps4 has in his sticky. Pretty great videos.
 
I am using the same set of software packages (alibre design elements and Bobcad/cam). I think its also worth noting that bobcad has a rather nice system in place for developing a post processor for mills that run non standard code. My anilam 3000m runs a conversational code but I was able to get bobcad to post to it. They had an existing post processor but there were a few errors. The system they have made finding and correcting the errors pretty simple. That said, I am a programmer, so the work is right up my alley.

Also, Bobcad offers educational prices that are worth looking in to for students/educators.

Brian
 
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