Building a High Speed Punch Press

JimDawson

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I normally don't get to post customer projects but I can in this case, nothing proprietary here. I just can't tell you exactly what it's for or show the tooling.

So what do you get when you combine about 150 lbs of steel, a high quality Harbor Freight 1 ton arbor press, a NEMA 42, 4200 oz-in stepper motor, and some electronics?

If I do it right, it will become a variable speed, 600 stroke per minute, 5/16 stroke, 1/4 ton punch press.

First you're gonna say that nobody in their right mind would use a HF press for the base, and I would have to agree. It wasn't my choice, but the customer insisted since he is currently using a HF 1 ton for the job and operating it manually. He wanted to keep the manual capability in case of a mechanical or electrical breakdown so I had to design around that. It will switch over to manual in about 15 seconds, you just have to install the pinion shaft. I suspect the HF press will break long before my hardware.

Here is what it's supposed to look like when it's done.

Press.jpg

The stack of parts. The motor weighs more than the press frame.
IMG_0495.jpg

I'll post pictures of the build as it progresses. The first order of business will be to get the mating surfaces on the press squared up so I can use them.

IMG_0495.jpg Press.jpg
 
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Seems like a very interesting build, can't wait for more updates.
 
awesome, thanks for posting this up! It sounded like a super cool project when I saw it in your shop and it'll be fun to follow it along :)
 
I normally don't get to post customer projects but I can in this case, nothing proprietary here. I just can't tell you exactly it's for or show the tooling.

So what do you get when you combine about 150 lbs of steel, a high quality Harbor Freight 1 ton arbor press, a NEMA 42, 4200 oz-in stepper motor, and some electronics?

If I do it right, it will become a variable speed, 600 stroke per minute, 5/16 stroke, 1/4 ton punch press.

First you're gonna say that nobody in their right mind would use a HF press for the base, and I would have to agree. It wasn't my choice, but the customer insisted since he is currently using a HF 1 ton for the job and operating it manually. He wanted to keep the manual capability in case of a mechanical or electrical breakdown so I had to design around that. It will switch over to manual in about 15 seconds, you just have to install the pinion shaft. I suspect the HF press will break long before my hardware.

Here is what it's supposed to look like when it's done.

View attachment 94132

The stack of parts. The motor weighs more than the press frame.
View attachment 94131

I'll post pictures of the build as it progresses. The first order of business will be to get the mating surfaces on the press squared up so I can use them.


Hope you can share what the die set looks like. Nice project.
 
Jim, interesting project.

With the advent of laser, industry is GIVING away punch presses. Why didn't the customer want to just get one of these?
 
Cool Project, Have Fun!
 
Jim, interesting project.

With the advent of laser, industry is GIVING away punch presses. Why didn't the customer want to just get one of these?


I tried to talk him into a little Benchmaster OBI or something like that, but this is what he insisted on.:nuts:
 
OK, I have one side of the press prepped for mounting my hardware.

Here is how I decided to hang onto it while I'm making chips.

I put the ram in the vice and indicated it in. Then I slid the press over the ram and tightened the ''gib'' screws. This puts everything else relative to the ram ways. This should give a repeatable locating method. Sometimes finding a starting point on a casting is a challenge. I supported the bottom of the press by clamping it to an angle plate. Then I put a jack screw under the web that I will be machine on. This made for a very solid setup.
IMG_0496.jpg

IMG_0502.jpg

A quick cut on the top of the pinion bearing just to square it up, I took off just enough to clean it up
IMG_0498.jpg

All of the dimensions are taken from the center of the pinion bore, so the next step is to center on the bore with the co-axial indicator.
IMG_0499.jpg

Prior to this I had no easy way of figuring out the radius of the flange on the pinion bearing or accurately locating it but once I knew where the bore center is, then I could find the edge of the flange with an edge finder. Once I had this information, I updated the drawing and prepared the g-code file to actually do some work.
IMG_0500.jpg

The first cut is to run a pocket routine to get a flat surface to mount the side plates. The surface was surprisingly flat, only out about 0.017 out. The outside of the flange was actually thicker than the inner part. I expected it to taper the other way.
IMG_0503.jpg

This takes confidence in the G-code and the machine accuracy, the endmill clears the vice by 0.015. I also did an air cut to confirm the clearance.
IMG_0505.jpg


The next step was a bit hairy, a 0.250 solid carbide end mill hanging out of the collet about 2 inches, a spindly little thing. This cleans up the flange radius so I have a locating point for the side plate. Wrapping the side plate around the casting a bit will strengthen the mount and take some load off of the attaching cap screws. The side plated will be stressed vertically in operation.IMG_0506.jpg

Once I completed the work, I milled a small flat on the back of the web for a datum point. I noted the location on the drawing so when I flip the press over I can locate off of the top, and that milled data point. That way if the pinion bore on the other side is not in line, I will still have known points to work from so my flanges are in an identical location on each side and everything lines up properly when I assemble the power head.

IMG_0508.jpg

Stay tuned for more fun!

IMG_0506.jpg IMG_0505.jpg IMG_0503.jpg IMG_0502.jpg IMG_0500.jpg IMG_0499.jpg IMG_0498.jpg IMG_0496.jpg IMG_0508.jpg
 
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A little more work on the press project

I flipped the press over and did the machine work on the opposite side, everything was held as in the first side above.

First set Z zero at the highest point that the tool could run into. Then set the clearance plane and Z park 1/4 inch above that. Z always parks before X -Y rapid move. That way when the table rapids to the assigned park position, and it won't smack the tool into something if I screwed up the tool path somewhere.

IMG_0509.jpg

Then find the height of the working surfaces using the tool as a probe. Put these numbers into the CAM program to set the Z positions.

IMG_0510.jpg

IMG_0511.jpg

Flattening out the web

IMG_0513.jpg

Once that was completed I had 3 parts to make out of 3/4 inch C1018 steel

When I design a part, if possible, I will line up any holes with the T-slot spacing in my mill table. In this case it worked out perfectly. I have a drawing of my mill table, and do an overlay to position the parts on the table.

Milltab.bmp.jpg

This is how I set my material.

First I center the spindle on a T-slot I will be using and set the DRO to the dimension on the drawing. It just has to be close because I always move the finished part back from the edge of the material a bit where possible. If it needs to be precision, I will make it precision by locating the T-slot with an edge finder and scribe the line with a height gauge and use my microscope in the spindle for positioning. It is rare that I have to do that. In this case I had over a 1/16 to work with, good as a mile. The old calibrated eyeball is close enough for this setup.

The drill bit is actually centered in the T-slot, the shadows make it look like it touching on the right.

IMG_0514.jpg

Then I set my square to the dimension on the drawing and scribe a line .

IMG_0518.jpg

IMG_0519.jpg

Now I move the material so the scribed line is under the center of the spindle. Again this only has to by close. Then I use the square to set the other end of the material to the same distance from the edge of the table. Then tighten the clamps.

IMG_0520.jpg

Once clamped down, I check the 0 edge for position. Looks good to me.

IMG_0521.jpg

Now I can drill all of the holes and install the hold down bolts. Center drill, pilot drill, drill, tap, and ream as needed. Once the material is bolted down, the clamps are removed.

IMG_0522.jpg

The first part has been roughed out, working on the third part. I am doing it in this order so there will be clearance for the loose pieces when they are cut off. The 1/2 cap screws are bolted through the 3/4 inch MDF backer and into the T-nuts. The two 3/8 cap screws on the left are just threaded into the MDF to keep the part from twisting, I could only put one hold down bolt in that part.

IMG_0529.jpg

All of the parts roughed out. 3/8 cobalt rougher endmill, 0.25 DOC, 2 IPM feed, and 120 FPM (1400 RPM) on the spindle. I probably could have gone through it in one pass with a 0.75 DOC and a higher feed rate, but I wasn't in that big of a hurry. I try to plan my tool paths so the loose piece coming off will not get jammed somewhere. I leave 0.025 for cleanup on a finishing pass, in this case with a 4-flute, 7/16, very high quality end mill from Harbor Freight.:lmao: Out of 3 new ones, I actually found one that was sharp.

IMG_0531.jpg

Finishing pass is done, and the holes have been counter sunk. I do the countersinking on the drill press, the counter sink pretty much just lives there in the chuck, much faster than doing it on the mill unless I need precision.

Here is kind of how everything fits together so far. I need to machine a pocket so the motor mount will clear the edge of the web on the press frame, then it will mate up to the side plates.

IMG_0534.jpg

There will be a motor mount pocket and a bearing pocket machined in where the hold down bolt hole is at right now. That is tomorrow's project.

IMG_0509.jpg IMG_0510.jpg IMG_0511.jpg IMG_0513.jpg Milltab.bmp.jpg IMG_0514.jpg IMG_0518.jpg IMG_0519.jpg IMG_0520.jpg IMG_0521.jpg IMG_0522.jpg IMG_0529.jpg IMG_0531.jpg IMG_0534.jpg
 
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