New PM-25MV Mill

[phazertwo]

I was hoping to avoid the respirator by getting it to run without fog... Does the coolant smoke at all when you are cutting? I need it mostly to keep the chips from sticking to the tool, actually cooling isn't as much of a concern. Does it lubricate the cutter as well as WD-40?

Also, do you dilute it at all before using it? Any discoloration on the part after using it? I can't remember which one it was, but one of the coolants turned aluminum parts brown.

I want to get some real coolant though. The WD40 is just what I have used with a spray bottle for the longest time and I had a gallon jug of it.

I diluted it 10:1, and it seems to be working great. It does lubricate well, and it didn't change the color of my parts. Hopefully I can get the mister dialed to the point that I don't feel like I need to wear a mask, but for now it's not constant enough.

Nice work on the motor, I'm very excited by this! I'm glad you're putting it to good use! Those cuts are looking really good, if you gear it down a touch like you were talking about you should find a bit more torque which will help. Of course getting it setup on 240v would be killer. You've really got me thinking about what to do with the other one!

As always, great work!

PZ

 

[shooter123456]

I diluted it 10:1, and it seems to be working great. It does lubricate well, and it didn't change the color of my parts. Hopefully I can get the mister dialed to the point that I don't feel like I need to wear a mask, but for now it's not constant enough.

Nice work on the motor, I'm very excited by this! I'm glad you're putting it to good use! Those cuts are looking really good, if you gear it down a touch like you were talking about you should find a bit more torque which will help. Of course getting it setup on 240v would be killer. You've really got me thinking about what to do with the other one!

As always, great work!

PZ

I will check it out, thank you for the tip! Their price does not seem at all unreasonable. When I was dialing in my mister, the pressure had to be crazy low to stop the fogging. I think I have it set to 8 PSI on the air line and about 10 PSI on the coolant tank. Even with the air line set to 15 PSI, it would fog like crazy.

I would love to see what the motor can do on a 940. I think I am going to run into rigidity problems long before I find the limit for the motor. I don't have a way to balance the spindle and tool holders at the moment, so I think I will limit the speed to about 8000 RPM. Right now it is geared 1:2.2. Their torque curve for the motor and drive at 120v stops at 2500 RPM (I was running at 3000), but if that graph is accurate, the motor was able to produce 3.39 Nm, which translates to 1.54 Nm at the spindle. Once hooked up to the 240v line, I will be going to 1:1.3 gearing, which at the same 6600 RPM at the spindle will give me about 2.25 Nm at the spindle. If I drop the motor down to 4000 with the spindle at 5200, it should give me 3.5 Nm at the spindle. The torque curve claims that at 2000 RPM, the motor can put out about 8.75 Nm, which should be plenty of torque at lower speeds. The motor also claims to have a top speed of 7000 with a slight reduction in torque, so that would give me 9100 RPM for using smaller cutters if I can balance the spindle a little better.

My Dad will be home this weekend and he is going to help me run the 240v line to the drive. I am going to make a separate electrical enclosure for the spindle drive to try to avoid noise and avoid building a new enclosure big enough to fit all of the electronics. Let me know if you need any of the info I used to get it running. Again, I can't thank you enough! This is a massive upgrade and I couldn't walk away from the machine since I was having such a blast turning scrap aluminum into chips.

 

[shooter123456]

I didn't realize I hadn't posted anything for so long... Whoops!

Since my last post I have:
1. Connected the servo drive to a dedicated 220v line (I keep saying 240, but I think its actually 220).
2. Run an AC line to the shop, no more 100 degree 80% humidity afternoons. Also I am not having any trouble with drives overheating.
3. Straightened the ballscrews, cleaned up the ballnut faces, and shimmed the nuts to increase preload.
4. Cut down the Y axis nut mount a little to slightly increase travel. I got about .375".
5. Started machining parts for a lathe attachment using the stock motor and quill bearings.
6. Machined a stepper coupler to connect to the Nema 34 shaft and mounted the Nema 34 Z axis motor.
7. Machined the second side of the AR15 lower.
8. Made a threadmill tool and threadmilled for the first time on the mill.
9. Made all 10 tool fingers for the automatic tool changer.

Connecting the servo motor to the 220v line did several things for me. First, it increased the output of the spindle motor to 2 HP from 1(ish) HP and the speed from 3000 to 6000 (Max speed actually 7000). Second, it took the spindle load off of the 120v lines in the garage. I was using 2 15 amp 120v lines to run everything in the shop. This meant that I could not run 2 of the larger power consumers at once (Milling machine, lathe, bandsaw, or air compressor) since any 2 at once would cause both of them to strain, or if the mill tried a heavier cut while anything else was on, it would trip the breaker. If I split the mill between the 2 120v lines (Spindle power on 1, control power on the other), when the air compressor kicked on, it would cause enough of a power flicker to cause the control computer to reboot. No bueno when it is cutting. Now, I have a free 120v line that can run the other machines while the mill is cutting on its own. So I can leave the compressor on to recharge, I can prep stock on the bandsaw, or work on the lathe while the machine is doing its thing.

AC in the garage is possibly the greatest thing I have ever done. In the past, I would soak through multiple shirts with sweat in one day and the machine would occasionally overheat the stepper drives. Now, its still warm, but much more tolerable. I have not yet insulated the door, but I can keep it around 80 to 85 degrees with the inside thermostat set to 75.

The X axis ballscrew was starting to concern me. The tail end would wiggle at least .250, if not more, when the table was farther to the right. It was also way too far out to support that end without binding issues. To straighten them, I took a pair of V blocks and a dial indicator and put them on my X2 table. I measured the point of max runout on the screw, then used the mill head to push on the highest point until it didn't spring all the way back. That took a fair amount of force. With the V blocks placed about 12 inches apart, the highest point was about .025" out and roughly 3/4 of the way down the screw on the drive end. Once I got that down to .005 or so, I just kept moving it back and forth until I found what point was the most out of round and pushing and working the screw into somewhat straight. Initially, I found 1 major bend, and 2 more minor bends (about .01" each). After straightening, I was able to get everything in to about .003" at the worst points. I didn't measure the machined end, but I wish I had. Once reinstalled, the far end of the screw wiggles maybe .01" and there is no longer an audible oscillation while the table moves.

I re-cut the faces of the nuts using soft jaws on the lathe. Most of the faces were rough machined and not ground, and looked pretty bad. The front of the flanged nuts on both were pretty bad too. I had to go off the assumption that the ball races would run true with the ground body of the nut. This may not actually be the case, but I didn't know how to measure off the ball races, and its not like I could make them much worse.

Here is the set up for the nuts facing. The nuts were definitely hardened, but cut well with carbide. In theory, the soft jaws ensure perfect (or at least very very good) concentricity.

Here you can see how far out the face of the nuts were. I had to take off about .015" to get it squared up.

Oh yea thats much better.

I always forget just how many fasteners the machine has and how many little components there are.

The extra shims preloading the nuts let me get the backlash on X and Y from about .0035" to .0015". I would like to get that even better, but I am happy with .0015.

 

[shooter123456]

I started working on a lathe attachment/4th axis for the machine as well. I am using the stock 1 HP BLDC motor and the large bearings from the quill for it. I have an idea for getting it to index automatically, but I don't think it will have full 4th axis capabilities. But 3+1 would be possible.

The 2500 rpm motor is going to be pulleyed down to 1000 RPM which should provide plenty of torque. I don't ever run my lathe faster than 1000, so I figured that would be plenty.

As with most of my projects, I started with some scrap plates. All of them had to be cut to size on the bandsaw before going on the mill. Who would have thought a little $150 bandsaw would be used so much and make my life so much easier?

I had to open up the bearing pocket for the front plate by about .002" for a heavy sliding fit (is that a thing?) I am very happy with that surface finish.

The rest of the parts were cut using a super glue fixture. Machining them was pretty uneventful and the machine ran on its own for a while with no issues. It probably ran for at least 6 hours that day.

Here is a look at almost all the parts and stock that will be used. I have not decided if I want to put a tapered bore on the spindle. I am trying to find a 2 piece jaw 4" 3 jaw chuck, but I have been unsuccessful so far.

I used a fixture to machine the second half of the AR15 lower. This was also uneventful (which is good) and it cut very well. Everything lined up nicely and it didn't move at all in the fixture.

I think there is a little bit of nod in the head somehow. It is trammed well left to right, but it might be off a little front to back. I am still happy with these finishes though.

This was one of the more interesting set ups I have done. I clamped my 3" toolmakers vise in the 4" vise, then used a clamp to hold the lower upright against the 3" vise. Here it is threadmilling the rear thread.

Its not the prettiest thread, but it works. I will need to buy a decent threadmill. They are a bit expensive though and I don't often need to threadmill.

I am thinking I will add another line for dedicated air coolant. With the mist, there is not enough pressure to clear chips from deeper pockets and it starts to recut chips if I don't blast them out with the air gun. I will just need some more locline and another solenoid valve.

I bought some stock to make a sheet metal brake to bend some sheet metal. I am going to try to make new way covers for both the Y and Z axis, as well as a cover for the head to keep chips out of the pulley and upper bearing. I have not decided how exactly I will do these covers, but I will figure it out as I go.

 

[shooter123456]

I got the 4th axis close to ready today. I machined the spindle shaft, finished the back side of all the 4th axis plates, drilled and tapped some holes, and did a quick test assembly. It is short 2 pulleys and 2 lock nuts before it can run. Then I need to find a 4"chuck with 2 piece jaws and/or come up with a vise to use with it.

Here is the shaft after everything but the front end machining.

Here is the backside of the rear plate being machined. It is cutting the face that will mount the motor.

Test assembly.

There's the repurposed spindle motor.

 

[macardoso]

Nice finish on the 4th axis spindle! What steel?

 

[shooter123456]

Nice finish on the 4th axis spindle! What steel?

Thank you! It is 12L14.

 

[macardoso]

Very nice! Just a thought, but you could either machine the pilot diameter for a front mounting bolt-thru chuck, or you could put a 5C taper in it.

 

[shooter123456]

I always thought that given enough time, these machines will pay for themselves. I had my houses backflow preventer inspected recently and it failed the inspection because one of the check valves was leaking. They said the ears used to install and remove them had broken off so it was damaged beyond repair. A new one runs anywhere for $250-$350. So I said to myself "I have all these machines, there has to be a way to repair this item that is damaged beyond repair."

First thing to do was remove the damaged check seat. It actually wasn't too hard. I just used the lathe to turn down a rod to the ID of the check seat, then superglued the rod to the rubber seat, and twisted it out.

I got a new check seat (actually an entire service kit with 2 check seats and o-rings and such) for $21. Turns out putting the new one in is kind of hard. But wait, they sell a tool for it! For $160... I said not today, parted off the part of the rod with the superglued seat on it, stuck it in the mill and cut 4 little grooves in it, then boom 5 minute later, the new seat was installed.

In my eyes, the 2 machines just earned at least $230 (a penny saved is a penny earned right?) with about 20 minutes of work. A shop rate of $690/hour isn't bad right?

 

[shooter123456]

In an attempt to finance some new machine parts, I thought to myself "Self, lets try to make a few kits for sale! Maybe there is a market out there!" So I have had the machine choochin hard for a few weeks now trying to get a few parts that looked great and make sure I have the programs all tuned in right. It is basically the same design as the one I have had on the machine for 7ish months now, except I added some chamfers and radii to try to make it look a little nicer.

I wonder if my idea regarding the kits is any good though. I would welcome feedback here. My thought is "I make the custom parts that need to be machined, then the user sources the hardware like ballscrews and bearings that are available through 100 different vendors." Theoretically, if you were looking to convert a machine and could save $200-$300 over the other offerings by sourcing your own hardware, would that be an attractive option, or would you prefer to pay a bit more and get everything all at once from one person?

Here's a few pictures of the parts so far. They all need a bit more work done and I need to make some flanges. I love how the chamfers from the 3/8" spot drill look. So much easier and cleaner than deburring by hand. The pics are a little dark because I turned a few lights off. Otherwise you can't see much on the part besides the reflected glare.