"One Perfect Part at a Time"

milling

CNC 4th Axis Update

The Taig CNC mill is closer to having its 4th axis operational. All that is really needed is to get the wiring completed. The tail post is not mounted where seen in the pictures. I was making adjustments to the height. You can see it is easily adjustable.

I will bolt down the tail post once I have an application where I need to use it. I now have the shims I need so a couple of bolts in the base and I’m in business.

When I have it running I’ll post a SHORT video to prove it works, Ha!  There is nothing more boring than watching 10 to 20 seconds of a CNC axis moving around doing nothing.

G-Wiz(ard) Wax

I had the chance to use the GWizard tool this weekend. I have been working on a wax mold project and thought it would be a great opportunity to optimize my speeds for milling wax.

There is no wax material guide in the tool but there is two kinds of plastic listed, both hard and soft. At first I thought soft would be good but as I thought about how wax actually mills, it acts like a hard plastic with the type of chips it makes. Soft plastics kind of gum up and take special consideration in my limited experience with them.

So I picked the hard plastic and started plugging in the numbers for the Taig mill and the cutting tools I am using. I used a 1/8 ball mill for roughing and a 1/16 ball mill for finish.

I was pleased to see there would be no problem running the rough at full speed (for me that’s 50 IPM) at 20% step. I am sure it could go faster. The spindle RPM on the Taig was 10,600. BTW it will run all day at that speed.

The chips were wonderful and very clean. I use a continuous air blast to keep the chips clear and the tool and wax cool.

My next goal was to get an excellent finish with as little bench work as possible. The GWizard figured out a 0.002” step over which is about 3.2% and a 20 IPM feed again at 10,600 RPM. It took me (the machine) two hours to run the finish pass in the picture.

With the air blast I never saw the chips in the finish pass. Just a very clean smooth area growing slowly as it worked 90 degrees to the roughing pass. I had left 0.020” for the… Continue reading

Milling Wax Adventure

The year is running out fast. I will soon have to say good-bye to 2011. This is the year (last Saturday actually) that I became 65 years old. Time enough for pondering that event, now to keep moving. Ha!

I did some machining of wax on the Taig CNC mill Saturday. I love machining wax (the hard blue kind). The wax is not good for creating real finished useful items but it makes excellent models for making molds and doing casting.

I spent the morning doing the design work in VECTRIC Aspire software. I was creating a Christmas ornament as a negative. I learned how to mirror and reverse the lettering and other “thinking inside out” processes in 3D design.

The afternoon was spent machining the design into the wax, using the Taig CNC mill. That was an adventure.

I haven’t run that machine for some time. The milling started out OK, but I got a couple of stalls and lost steps in the Z axis. The mill has never done that before so it was a surprise. I wasn’t pushing rapid travel or cutting speeds that hard either. Lifting the spindle and motor is fairly hard work.

The rapids are only set at 65 IPM and I was running about a third of that. So I ran through the software set-up and MACH3 warned me I was pushing the limit on pulses for the pulse generation frequency for which I had MACH 3 set. The Taig has twenty TPI screws so it takes a lot of very short pulses with 1/8th stepping (32,000 per inch) to get any speed from the drives.

That’s 32,000 per inch so at 60 IPM travel (keeping the math simple) that’s 1 inch per second requiring 32,000 Hz (32 kHz)… Continue reading

GWizard – First Looks

A visitor to this blog named Bob Warfield left a comment about a post he made in his blog HERE. Bob is also the creator or progenitor of machine shop “Speeds and Feeds” software called GWizard. It probably isn’t fair to call it just a Feeds & Speeds as it does so much more.

Bob told me he was known for The CNC Cookbook Blog as well as anything. So naturally I had to dive in and take a look. Sure enough there was Bob standing there grinning and holding plate with pumpkin pie. You’ll probably have to scroll way down to find him now (and the pie). This CNC Cookbook is a great place to read and study about the “science” of rotary machining.

I like a guy that doesn’t hide his face from his peers and customers.

I perused carefully everything I could find on that web site. Where was this when I needed it!? Of course always the skeptic, I had to figure out what was the “deal” going on here. The biggest question for any CNC machinist (well at least for me) is how hard can I push feeds and speeds and what are the reasons. It would seem obvious that this sort of program would have been offered long ago. But… it is a very complex subject. Tool manufactures are of course going to shade any such tool program toward their own products.

Bob admits it could be done with a spread sheet and in fact that is how he started. When I first started CNC machining I eventually found the safe speeds for the kind of work I usually do, but it had taken a lot of effort. I could have built a spread sheet myself but the effort would have kept… Continue reading

“Proofs” of Concept

I was doing some product research today. This is something I made in about five to six hours. I had been thinking of how I was going to make these all week. I just needed a good Saturday to give it a shot.

As the title indicates this is a proof of concept not a real project. I didn’t want to slow myself down doing all the pictures of the process. The process is still experimental so  full disclosure can wait until a better time. I have my camera at the ready.

Long time readers know I have experimented with pewter casting before. Here is the LINK.

The “thumbs up” graphic is a 3-D rendering received free with the Vectric Aspire software. I used it to create the medallion. The finished result is seen in the first picture above. The picture was created within the software. I combined the thumbs up with some freelance drawing to form the disk. Actually in my opinion the disk is much thicker than it should be.

The edges of the disk did not come out well in the tool pathing. I need to find a better way to create the disk in the software. As this was a trial, I didn’t want to spend all day on the drawing so I accepted some imperfection in the edge rendering and moved on.

Next I had Aspire produce a roughing toolpath for a 1/8 inch ball nose mill bit. Then I had Aspire produce a spiral finish pass with a 5/32 inch ball nose. The disk is 1-1/2 inches in diameter. The aluminum (both pieces) is 1/4 x 3 x3 inches. The back plate is not machined in this test trial.

The machining was done on the CNC Taig mill. A… Continue reading

Categories
NOTE: Log in is for admin and members only, not required to post comments.