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Servo Punch Press

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JimDawson

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#1
A customer asked me to build a special high speed punch press for punching some plastic parts from a strip. I can't go into any product detail, but I can give the general specifications for the machine.

Target speed: 600 hits/min, more realistically 300 or so I'm guessing.
On-the-fly infinitely variable feed length from 1 inch to 6 inches
Easily adjustable for different punch patterns.....More on this later.
Because it's punching plastic, a push-pull feed system
1.8KW servo drives on both the feed and crankshaft drive.
Touch screen operator interface.
2 axis Galil motion controller

Just a teaser picture...I'll post more later

One of the side frames 12x20x1 A36 steel
1536272287686.png
 

vtcnc

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#2
A customer asked me to build a special high speed punch press for punching some plastic parts from a strip. I can't go into any product detail, but I can give the general specifications for the machine.

Target speed: 600 hits/min, more realistically 300 or so I'm guessing.
On-the-fly infinitely variable feed length from 1 inch to 6 inches
Easily adjustable for different punch patterns.....More on this later.
Because it's punching plastic, a push-pull feed system
1.8KW servo drives on both the feed and crankshaft drive.
Touch screen operator interface.
2 axis Galil motion controller

Just a teaser picture...I'll post more later

One of the side frames 12x20x1 A36 steel
View attachment 275030
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JimDawson

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#3
A quick overview of the electrical
The basic panel layout, DMM DYN4 1.8KW servo drives, and the rest of the hardware is from Automation Direct
1536336509398.png
The DMM 1.8KW servo motors, and other bits & pieces
1536336550754.png

The fanless micro computer w/Win10 and a 10 inch touch screen.
1536336584664.png
 

rgray

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#4
Watching with interest.
 

JimDawson

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#5
I had to drill & tap four 3/8-16 in the top of the frame to secure the top cover plate. The only machine I have with enough height to handle 22 inches is the old Harbor Freight drill press. It normally has a counter sink in the chuck for deburring, almost never actually drills holes.

1536365150828.png

So first beef up the DP table a bit, don't want to break it off when I set 150 lbs of iron on it.
1536365361195.png

I got the holes drilled & tapped and I didn't kill the DP :)

1536365413980.png
 

FOMOGO

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#6
Sounds like a challenging project. Nice work, making do with what you have on hand. Mike
 
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JimDawson

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#7
The next part is the connecting rod. Material = 4150, so we start out with a chunk 8 1/2 x 4 x 1 1/4.

1536592896371.png

First mount up a ''spoil plate'' in the mill vice to bolt the work to. The aluminum is just a piece of stock I had on the shelf, when done with this project, it will go back on the shelf and get used for something else.
1536593185284.png

Face off and drill & tap 1/2-13 mounting, the side holes will be used later. Since there are several operations, I spent quite a bit of time ''machining'' the part in my head to get the order of operation and work holding correct. I set the stock on top of the aluminum aligned it and clamped it down, and set the 0,0 at the top right edge. Then I scribed a line and witness marks to be able to locate the part again. This insured that the holes in the aluminum and in the stock agree in location. This 0,0 location will not change until the job is completed.
1536593404286.png

Since the entire outside needs to be profiled it gets bolted down at the bearing and pin ends. That allows access to the entire outside and for other operations. The bearing bolt is counterbored deep for a reason.
1536593510096.png

Then I took a 0.010 deep pass to mark the profile, then unbolted the part and over to the band saw to remove the bulk of the material to save spindle time.
1536594069987.png

Then back in the mill to run the roughing passes. The bolts don't have a lot of clearance, but I'm sure the part did not go back on exactly the way it came off, but it doesn't matter, the OD will clean up to size on finishing and everything else will be relative to the current location. Using a 1/2 rougher, full depth, with about 0.050 width of cut.

1536594397727.png

And the finishing pass, 5/8 Harbor Freight 4 flute. It's what was in the holder. :)
1536594594516.png

The crank end is 18mm thick, but the pin end is 1.25 so half of the difference needs to be removed from each side of the rod. So remove 0.270 in two pocketing passes with a 3/8 rougher. Now you see why the bearing end bolt was counterbored deep.

1536595042648.png

Then pocket out the center web another 0.250 deep just to remove some mass, and do some other cleanup in preparation for machining the radiuses with a 1/4 ball end mill.

1536595290550.png

Machining the radiuses, don't want any sharp corners that would cause stress risers.
1536595403549.png

And the first side is finished. Now it gets flipped over and the same operations are performed on the other side.
Then once that work is done, the bearing and pin holes will be bored.

1536595519777.png
 

BaronJ

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#8
Hi Jim,

If that were me drilling the holes in the top of that hunk of metal, I would have put it on the foot of the drill and dropped the head down to suit !
Reminds me of drilling out holes that were too small in a propshaft spider that was already welded up.
 

JimDawson

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#9
Hi Jim,

If that were me drilling the holes in the top of that hunk of metal, I would have put it on the foot of the drill and dropped the head down to suit !
Reminds me of drilling out holes that were too small in a propshaft spider that was already welded up.
That would work. The problem with doing that on that particular drill press is that the head won't drop without extensive modification. :)
 

BaronJ

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#10
Hi Jim,

Oh thats a bugger ! My floor standing drill press at the time was a "Fobco Star" 1/2" with a column that passed through the drill head. That made it easy to lower it, right to the floor if needed. I originally had three of them, two floor standing and one bench mount. I kept the bench mount one !

The number of times I wish I had kept one of the others. Annoyingly the floor standing ones were a couple of years newer with 16 mm chucks, and bigger tables.

Edit: Sorry it is the bench one with the 1/2" chuck.
 

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#11
OK in the previous post one side of the connecting rod was finished, so now is time to do the other side. So first mill a con rod shaped pocket into the aluminum. 0.125 deep and a loose press fit. This locates the part exactly back relative to 0,0 without having to dial anything in after it's turned over. The screwdriver pockets are so it's possible to get the part out of the aluminum block, you need to pry it out.

1536637997775.png

The same operations were performed on this side as the first side. I left the ''island'' on the crank end because I didn't have enough meat in there to counter bore for a screw. So I used flat head screws on this side for tool clearance.

Also you now see why the side screw holes were there. All they have to do is hold the part down, the pocket holds it in location. The next step is to pocket and bore the bearing and pin holes.
1536638620284.png

While the con rod was running, I was setting up to fab up the feed rollers in the lathe.
12 x 4 inch dia 8620. This was another bit of a screw up on my part, originally I designed the rollers to be 3.800 dia, and ordered the material. After a design review I decided to make the feed rollers 2.75 diameter so I'll be making a lot of chips to get this down to size.

Does this look like too much stick out? :grin:
1536638933498.png

Yeah, I guess it is. :cautious: Note: The chuck jaws are at the absolute limit of extension where I will run them. So support it in the steady rest to face and center drill. For center drilling I normally face a small area, in this case about 1 inch dia. Then center drill and then finish the face after the center is in place.

1536639032076.png
 

JimDawson

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#12
Finishing the connecting rod

First I profiled the big end bore to remove the material as efficiently as possible without having to turn the entire volume into chips.

1536805526970.png

Then I drilled the pin end with a 1 inch drill then to out a bit more by profiling the bore. Final diameter is 1.250
1536805651306.png

Then bore to size. Using a 3/4 inch 2 flute endmill for a boring bar. Nice and stiff and sharp. You just have to get the tip of the set at the correct angle. Works great, I use endmills in the lathe for boring bars also when doing shallow bores.
1536805917673.png

And the finished rod with the bearings pressed in, bronze flange bearings in the pin end. I reduced the mass of the 8 1/2 x 4 x 1 1/4 raw material by about 65%.

1536806301957.png
 

FOMOGO

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#13
That came out great. Thanks for the walk through of all the operations. Mike
 

JimDawson

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#14
Thank you Mike. It's my pleasure to try to show some tricks & tips.
 

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#15
The next part of the project is to make the driven feed rolls.

The original design called for 3.800 dia rolls so I ordered a foot of 4'' dia 8620. Well I changed the design so now the feed rolls are 2.625 dia. Had to make a lot of chips. This stuff cuts nice, tough, but didn't give me any problems once I figured out the feed & speed and depth of cut. I could only take 0.050 off of the diameter per pass on my lathe.

First face and center drill for the center. When doing something like this, I just face a small circle around the center, no need to face the whole end, the saw cut was pretty straight. Just need a flat surface to keep the center drill from walking around.


Then turn down to 3'' dia for roughing out.
1537062236632.png

Then over to the band saw to cut into part sized pieces. Once back in the lathe, do the work on the front end and bore for the shaft. The bore will now become my base surface. The bore and counterbore are concentric, but the OD is subject to the runout in the chuck (about 0.003), that's why to OD is only roughed out at this point. For the finished piece, the bore and the OD must be concentric.
1537062625740.png

Then flip it around and machine the step on the back. The OD of the step does not have to be perfectly concentric to the bore, it just holds a couple of set screws, chuck tolerance is good enough.
1537062866214.png

Once I have the part to this point it's ready to key, I didn't get any pictures of that operation. I have a Dumont broach set and a broach press. Here is a picture of the broach press, configured as a mini press brake in this picture. Built from a Chinese wood splitter. Not much of a wood splitter, but makes a great long stroke 7 ton arbor press.
1537063765501.png


Then over to the mill. This is the shaft that the roll will run on in the machine. First mill the keyway.
1537063910186.png

Then D & T the set screw holes. I set up the spindex because I wanted one hole over the key, and the other at 90°. The part is located off of the edge of the vice so the spindex only needs to kinda hold the shaft. I just shimmed it to the right height. This is the first time I have used the spindex, I've had it for 25 years :) Had to clean it up a bit before I could use it. I's been sitting in the back of the bottom shelf of the tool cabinet for a long time.
1537063977410.png

Then back over to the lathe with the shaft in the collet chuck. If I didn't have an accurate collet chuck I would have either used the 4-jaw or turned a stub arbor in the 3-jaw to have a concentric shaft to mount the part on for finishing. This is the best solution because the roll is mounted on the shaft that it will be running on in the machine, so the best concentricity that I can get. This chuck has about 0.0002 runout (after I reground the bore). Now I can finish the OD.
1537064691007.png

Once the OD is turned to size then knurl so it grips the material. The two rolls are slightly different sizes, I want to outfeed roll to pull a little faster than the infeed roll. About 0.5% difference in the circumference. This should prevent any tendency for the material to buckle as it feeds through the press.

The shaft tried to walk out of the chuck during this operation, so I moved the tailstock center into position for a little added support. Running at 70 RPM with a slow feed. Using heavy sulfur cutting oil. I start with about 1/2 the knurling roller on the part and feed towards the headstock, then feed until about 1/2 the knurling roller is off the part on the other end. Then stop the chuck, reverse the feed, and run back to the start point. If needed, go a bit deeper and run again. I did these in two passes. Don't retract the knurling rollers from the part until you're happy with the result, it will screw up the pattern. I need to buy some new knurling rollers, these are junk, the center hole is about 0.010 off center. The holder is fine.
1537064987282.png

And the finished parts
1537065645814.png
 

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#16
Next is the real heart of the press, the ram. This press is unique in that the die is integrated into the press rather than being a seperate part as in most presses. This is a single use press so this works out well. This means that there is no margin for error and the tolerance stackup has to be minimized. I have been doing surface grinder quality work on the mill, have been holding +/- 0.0001 on the critical dimensions. The good news is that properly set up, my machine will hold those tolerances.

The first step in the process is to get the fixture block set up, the same chunk of aluminum I used to fixture the connecting rod, I just used the other side.

The nut for the wrist pin nut is the item to be made, 2 inch 1018 shafting. The fixturing holes are already drilled & tapped.
1537461694308.png

The nut mounting holes done.
1537461778012.png

Then pocket clearance for the nut so it can be attached to the rear ram plate, this way it can be drilled & tapped in the same setup as the pin hole in the ram plate, this insures that everything is concentric.
1537461983413.png

Aligning the ram plate on the machine 0,0. I just scribed lines in the proper place to set the 0,0 point, nothing critical here because the piece is oversize at this point.
1537462186118.png

Then drill and C-sink the mounting holes. Using flathead screws for tool clearance.

1537462304637.png

I screwed the part down and took a shallow profile cut to get an outline and drilled & tapped the nut mounting holes. Then over to the band saw and cut out the part and attach the nut. Again nothing is critical at this point because the part is just roughed out.

1537462549385.png

The finished part. The sides, bottom, and pin hole location relative to each other are the critical dimensions. 1 inch shoulder screw.
1537462765188.png

Then I made an identical plate for the front side without the nut.

Then I made two spacer blocks that will hold the spacing of the two ram plates correctly for further operations. These will be used later to mount the bolster plate.
1537463043293.png

Now I can drill & tap the holes for the linear bearing blocks and the bottom plate. I used a couple of 1/4 '' flathead screws to hold the assembly together.
1537463348760.png

The bottom plate, also drilled & tapped for the punch holder. I have been able to drill the dowel pin holes and have everything line up, good repeatability.

1537463519729.png

And the finished ram assembly.
1537463624054.png
 

JimDawson

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#17
Next the punch holder that attaches to the ram.

Still using the same aluminum fixture block, I had it pre-drilled & tapped to accept this part. This is a chunk of 4150, same material as the connecting rod. Clamped a larger chunk to the fixture drilled & c-sink, and drill & ream the dowel pin holes. Then did a shallow profile cut to mark the OD, then cut it out on the bandsaw. Then bolted it back down to the fixture for finishing.

1537499358649.png

Then drill, straighten, drill & ream the 7 punch holder holes. Straighten? After drilling the pilot holes at about 0.170, I went in with a 0.187 endmill to insure the holes are straight, then drill with a 0.236 drill prior to reaming. Then ream with a 0.2495 reamer to fit the 0.250 punch shanks.
1537499882726.png

Once the holes are reamed then flip the part over and mill the clearance for the punch heads.
1537500010036.png

And there it is..... the ram installed in the press. The action is silky smooth, I'm happy with the way it came out. Everything fit as planned.

It's really too bad that all of the really cool work is going to be hidden inside the covers.

1537500332131.png
 

JimDawson

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#18
I kind of started this thread in the middle of the project so here are some pictures earlier in the project.

Here is the stand that the press will be installed on. 2x2x1/4 square tube. Took me about a day to fab this up.

1537500831040.png

The press frame showing the crank housing and motor mounts.
1537500985532.png

Fitting the feed system and linear bearing rails
1537501107395.png

The rear view with the motors in place.
1537501175350.png

The crankshaft, made from 3 inch 4340.
1537501477920.png

Once the steps are done on the right side then go in and nibble out the the left bearing journal. Just plunge a bit with the tool as you are moving the carriage back & forth a bit while plunging in with the tool bit. The crank journal is left at 2.125 inch to be able to turn the eccentric.
1537501609074.png

Once the journal is roughed out and tool clearance turned, then go in with the right hand radius tool to finish and put a generous radius in the the corner.

1537501968204.png

Then setup the steady rest and drill & bore the motor end. This will press directly onto the motor shaft. Got a little hot when I was drilling it. :)
1537502119505.png

Once cut off in the band saw, I built a plug to go in the end so I can clamp it in the 4-jaw without squishing the end. The threaded end is so I have something to grab onto to pull the plug back out.
1537502363978.png

Then set up in the 4-jaw to turn the eccentric. To insure the part is pointing directly at the tailstock, both bearing journals are measured to make sure they are in the same plane. This is done by dialing it in then bumping the part with a dead blow hammer until it's lined up properly. The offset is supposed to be 0.375, but 0.3755 is close enough. Took about a half hour to dial in to this point. The bearing journals are 30mm and the crank journal will be 40mm, that way the the connecting rod will slide over the bearing journal onto the crank journal with 0.010 clearance.

1537502885164.png

The center drill is on the spindle centerline. looks a little weird :)
1537502967673.png

Starting the eccentric

And finishing

And the finished crankshaft. I didn't get a picture of slitting the sleeve that presses onto the motor shaft. The crank bearing is a tight slip fit on the crank journal. It has to find its own center so could not be pressed on. The bearing journals are a light press fit as are the crank housing bearing bores.

1537503673195.png
 

JimDawson

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#19
With the ram installed in the press, now I can locate the lower die holder. But first it needs a bolster plate to support the die holder. So first make the bolster plate mounts. Normally you would bolt the bolster plate directly to the press frame, but in this case it's impossible to drill any mount holes in the press frame because of narrow opening. So I need to finish the bolster plate mounts that I used to space the the ram when I was building it.

I needed them spaced 4.0190 apart to make sure the hole pattern is correct to match the press fame spacing and more importantly that the dowel pins are in exactly the right place. No way in this case to put in the dowel pins after bolting in place. So two 123 blocks and a couple of 0.019 feeler gauges makes the 4.0190 spacing I needed. So indicate everything in to make sure the work is square with the vice and locate the edges of the R/H part, and set the 0,0 on the top right corner.
1537847799996.png

Then drill the holes, ream the dowel pin holes, tap as needed and break the **** tap on the last hole:mad: https://www.hobby-machinist.com/threads/yall-aint-gonna-believe-this-one.72951/
1537849302429.png

So after a small mishap in building the bolster/die holder fixture https://www.hobby-machinist.com/threads/moving-a-hole.72977/#post-612155 the bolster plate is complete.

1537849685009.png

So now comes the real fun. The die holder needs to be located relative to a punch. So this means locating a point in space. I know where the drawing says it should be, but because of the tolerance stackup there is no guarantee it is where it should be and I need to locate it +/- 0.0005. Everything now is relative to the upper right dowel pin in the picture above, that is 0,0 for the rest of the operations. That point will be 0,0 for the the bolster plate, the die holder, and the stripper plate. In a normal press & die setup the die set would be a completely separate build, but in this case the die is built into the press to reduce the moving mass for high speed operation.

The bolster plate is bolted into position, and the ram is lowered so the punch is touching the plate. Only one punch is installed, that's all that's needed to find the location.
1537850977772.png

Next measure the punch location in the X & Y axes
1537851835934.png

Then over to the mill, using a dial indicator and the DRO locate the front and side relative to the dowel pin.
1537851966190.png
Record the numbers from the DRO on the part with a sharpie :) Then update the drawing with the new values. This then becomes the base to make the die holder.
1537852028320.png

The die holder is made from 3/4 inch 4150, and is set up on the fixture plate. The two top dowel pins locate the part during machining, they won't be used for locating the die holder on the bolster plate, not accurate enough. There will be another set of dowel pin holes drilled & reamed once the die holder is aligned in the press and bolted down to the bolster plate. The bolt holes are drilled to 1/4'' standard free fit clearance using a H (0.266) drill. This gives some wiggle room for final alignment of the punches and die before the dowel pins are installed to lock the position.

The small holes are drilled & reamed to accept the die buttons, the large die button hole will be done in the morning. A little tiny die button is sitting next to the hole. Never seen one that small before but because of the lack of room around the large die button I had to go with these.

That surface looks rough, but it's really as smooth as a baby's bottom. If I had used a sharper end mill, the little tool swirls would not be there.
1537853075758.png

Tomorrow the stripper plate/ punch guide :)

More later.........
 
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JimDawson

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#20
The die holder, really a pretty simple portion of the system. 7 holes to take the 7 die buttons. The center hole needs to be machined to take a 3/4'' OD die button. The somewhat tricky part is the holes have to be very accurately located and on size to allow a normal press fit of the die buttons. So again using the upper right dowel pin as 0,0, Carefully spot drill, drill, straighten with an end mill, and ream to 0.1875, the die button's OD are 0.1878. Makes a nice snug fit.

1538015015554.png

Then drill and pocket the center die button. This is one of those holes you have to sneak up on. It can not be oversize, nor too tight. So make a cut, measure, adjust tool offset, cut, measure, adjust tool offset, rinse repeat until done. Target size 0.7503 for a 0.0005 press fit, the die button is 0.7508 OD.
1538015411030.png

Next is the stripper plate/punch guide. When using spindly little punches it's a good idea to build in a guide for them, and especially in this case where the die is actually part of the press. The purpose of the stripper plate is to strip the material off of the punches as they pull out of the holes. In many cases the stripper plate is spring loaded and built into the upper die half. But in this case the material doesn't need a lot of overhead clearance so this system is the best and allows the punches to be captured by the guide holes. The punches will never pull completely out of the stripper plate.

This is temporarily bolted down until I can counterbore the other 4 mount holes for facing. location at this point is not critical because the material is still about 1/16 oversize. This is the bottom of the stripper plate. It gets a 0.100 deep slot down the center as a material guide, 0.010 wider than the material. The material is about 0.065 thick.
1538016364398.png

Now flip it over and do the work on the top side, and and finish the OD. Then drill & ream the small punch guide holes, these are 0.002 larger than the punches. Then pocket the guide hole for the large punch. Because the stripper plate and the die holder are both done in the same setup and the stripper plate is doweled to the die holder it's pretty hard to screw up the locations. The 4 mount holes in the center were only used to secure the part during machining, they won't be used for securing the stripper plate. They also allow access to the screws securing the die holder to the bolster plate so that final alignment can be done before dowel pinning everything in place. Thinking ahead and order of operation is important to keep from painting yourself into a corner :)
1538017331560.png

And completed
1538017923664.png

I did make a bit of a tactical error in the design, when I was trying to align the punches and dies I found the press frame was out of square. I thought the 1 inch thick top plate would hold it square, but that's not the case. So I need to build a crossmember that will cover the crankshaft housing and fit tightly between the frame sides, and get bolted and pinned into place. This will also set the spacing on the frame halves so the height adjustment works smoothly, it's a bit tight right now. I just happen to have a piece of 3/4 A36 that will fit in there nicely. :) The hardware was backset 3/4 inch to allow clearance for the wrist pin (shoulder bolt) head so I could screw the lexan guard directly to the frame.

1538019671629.png


And all of the punches installed and aligned. This area of the press is completely finger safe, as said above the punches will never pull out of the stripper plate, and the absolute minimum shut height is > than 1 1/4 inch. But it will still have a lexan guard on it. :cautious: Even without the guard this was designed to have no pinch points.
1538018067754.png

More later...
 
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JimDawson

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#21
Today was build a crossmember day :) (see post above) This is a piece of A36 steel, 6x12x3/4. It needs to get trimmed down to 5.4625 x 11.5 x whatever makes it flat after facing.

So the first operation is to put it in the vice and face both sides to remove the mill scale and flatten it out, most flat bar has some bow in it. It finished at 0.714. I didn't get any pictures of that operation, but you know what a carbide insert face mill looks like :)

Then anchor to the fixture plate and rough cut the OD. Had this been wider than the vice I would have bolted it to the table with the aluminum under. Then the finishing pass on the OD, this pass is taking of the last 0.0005 per side to finish. This is called doing surface grinder work on a mill :grin: ( I have two surface grinders, but neither of them are set up). This again is one of those dimensions that you need to sneak up on, it must be on size. Nice sharp 3/8 solid carbide end mill, ~140 SFM (1420 RPM), 6 IPM feed. It came out on size :).

1538107916129.png

This was bolted down to a 1/2 scrap aluminum piece that was used for a fixture for another project, this allowed working around the entire perimeter.
1538108070646.png

The next step is to machine clearance for the ram since this will cover the entire front of the press. 0.150 deep x 6 inches. The bottom 1/4 inch of this poor old roughing end mill has just about had it. Wasn't sure it was going to finish this cut.
1538108841417.png

But the rest of the end mill is nice and sharp so drop it way down through the hole to cut the bolt head clearance.
1538109044685.png

And the top view
1538109115680.png

And last, I need to cover the bolt head clearance hole because this just created a pinch point, so screw a scrap piece of 3/8 lexan down to the pre-tapped holes and profile the OD. Access to the bolt is required for machine maintenance. This cover actually installs on the other side.

1538109743783.png

Tomorrow the crossmember will be installed on the press, 12 hours is enough for today :)
 
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JimDawson

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#22
Today I installed the crossmember, it worked as planned. I had to do a bit of prep work on the frame sides to install. so pull the sides one at a time and over to the mill to drill & counterbore the mount holes.

So set on the mill table spaced with some 123 blocks. The dial it in and locate the lower left corner for 0,0. Then do a bit of measuring to confirm that the side plate matches the drawing. Well it didn't :mad: The entire area bounded by the calipers is screwed up. Which explains one of the problems I was having aligning the die. This goes back to what I thought was a backlash problem with the mill. https://www.hobby-machinist.com/threads/another-backlash-problem.72171/#post-606271. The holes and more importantly the frame edge to the opening edge was not located correctly. The good news is the I could fix it by removing metal, needed to take about 0.010 off. The opening is just a bit wider now, but the dimension from the corner to the opening is correct, and now matches the other side.

BTW, those are Harbor Freight 12''calipers, about $20. A bit stiff, but seem to be pretty accurate, had to adjust them to align the jaws, but that only took a minute.
1538283782138.png

I had to move the bolster mount holes a bit also. I just pocketed these since I was already set up. 1/4 inch solid carbide router bit from Home Depot.
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Here is what the press looks like on the inside with the left side removed. It don't look like much, but a lot of work in there.
1538284545612.png

And the stiffener installed. Works great, holds the press frame square.

1538284608517.png

And the guard over the pinch point................BUT... There is a couple of problems with that guard. https://www.hobby-machinist.com/threads/machine-guarding.73128/
1538284794599.png

More later......
 

JimDawson

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#23
A bit more progress, after doing the rework on the side plates I was able to finally get the die aligned with the punches and get it to do so repeatably. Everything is now dowel pinned in place.
1538455854218.png

So now I need to put a 1.375 radius on each end of the die holder to clear the feed rolls. So run a profile routine to do that. Material 4150, 3/4 x 4'' HSS endmill, 340 RPM, 2.5 IPM, 0.060 DOC, 0.050 step over. Total depth about 3.625. Took a while per pass about 82 minutes per, 3 passes. I roughed it out on the band saw first.
1538456657756.png

And done
1538456698244.png
 

JimDawson

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#24
I haven't updated this for awhile, been busy trying to get this thing out the door. My customer is getting a bit antsy, I'm way overdue on shipping.

Where I left off above is prepping the the holder to accept the feed rollers. The ends were concave radiused for clearance. The rollers need to stick up above the top of the die holder about 0.030 or so.

Here is a picture with the feed rollers installed and the retractable top pressure rolls just sitting in position.
1539577397856.png

The next step is to build the mounting system for the pressure rolls. The toggle clamp will be used to retract the pressure roll for loading the material into the machine.
1539577942486.png

So first grab an old rusty piece of 3/4'' A36 and clean it up to look a bit presentable and prep it for the next operations...... Building the mounting brackets. So now I have 4 blanks for the mounting brackets and an aluminum fixture in the vice. Since I'm doing 4 identical parts, I'm using dowel pins to locate the part on the fixture while machining, it's held in place with two 1/4'' cap screws, the dowel pins prevent any lateral movement, the cap screws only have to prevent it from lifting. Notice the two screwdriver slots in either end of the fixture, this allows easy removal of the part from the dowel pins.

So first make a light cut of the profile, then over to the band saw to rough them out, actually saves time to do it that way and I don't eat as many endmills.
1539578610349.png

After bandsawing
1539578664502.png

Then rough and finish profile.
1539578747825.png

I didn't get a picture of the slotting operation or the various drilling operations. There is a 1'' wide slot in the bottom of two of the pieces, and a 3/4 wide slot in the in the other two and a 3/8'' hole drilled from the top that intersects with the center of the slot in all of the pieces. After inserting the die springs, I also installed threaded 1/2-13 x 3/8-16 in each piece for the spring adjuster screw. This holds the tension on the spring to press the roller shaft down.

The next operation is the roller shafts. There are turned down to 0.750 on one end to accept the roller bearings that press into the roller bore. Then mill the spring landings and pull attachment point. Also mill the anti-rotation flats on the off roller end, thus the need for the spindex.
1539579496358.png

And installed on the press. I cut the heads off of four 3/8 cap screws and cross drilled them to accept a #40 chain master link. I needed a flexible link and that seemed like the easiest way to do it. The toggle clamp handles are in the normal operating position, push them up against the press frame to raise the rollers. In the bottom of the back mounts is a ball end set screw that sits in a divot in the shaft. This allows leveling adjustment of the roller, without it the pressure rollers would not sit parallel to the feed rollers. They work exactly as planned.:encourage:

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Another view
1539582714650.png

I have it running now and making product. Have had the normal software glitches and a rather odd control problem. It turns out that the servo drives are so electrically noisy that when turned on they kill my ethernet connection to the motion controller, I have everything grounded properly so this one is a bit puzzling. The work around for that seems to be to use the serial connection on the controller, but that causes some other minor issues in communication speed. I need to find a better workaround. But overall it's a success. I ran out about 1100 feet of product yesterday in just over an hour running at about 1/3 speed, so I can say it works. I should be getting about 12,000 feet of material tomorrow so as soon as I figure out the material handling I'll run that and then ship the machine, and the finished product to the customer.
 

Dabbler

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#25
seriously great work!
 

whitmore

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#27
...I have it running now and making product. Have had the normal software glitches and a rather odd control problem. It turns out that the servo drives are so electrically noisy that when turned on they kill my ethernet connection to the motion controller, I have everything grounded properly so this one is a bit puzzling. The work around for that seems to be to use the serial connection on the controller, but that causes some other minor issues in communication speed. I need to find a better workaround.
Excellent! As for Ethernet, it should tolerate hundreds of volts without problems (grounding shouldn't matter), whereas
a serial link only tolerates a few volts. I'd suspect a bad cable, first.
 

Reddinr

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#28
I'll just toss out some ideas. Sometimes an inexpensive fix for this sort of noise problem is to fit toroid cores (ferrites) on either the noise source (motor leads) or the susceptible cable (ethernet) or both. Signal and power wiring separation can help too. It is also possible the ethernet cable isn't the way the noise is being picked up. The noise could be conducted into the power supply or control IO of the controllers or computer. A little trial and error with ferrite cores and being sure that noise source cables are separated by some distance from signal cables might help. Also, if some control wiring is not shielded, consider shielded wiring. Be sure shield lead drain lead connections are very short and that the un-shielded sections of the cable near the terminations are as short as possible. From a grounding stand-point, a star type ground is generally better than a daisy-chain ground. One last thing. It is possible to lock the ethernet nic to a slower speed such at 10 Mbps instead of the automatic 10/100 or 10/100/1000 setting, if you don't need that speed. I have used that technique before. It worked once for one problem system I had but did not work on another.
 

Boswell

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#29
This might be a bit of hair splitting but I strongly doubt that the noise is being picked up by the ethernet hardware layer. This is because Ethernet, like RS-485, USB and some other protocols uses a Differential Signal technique . This means that two wires are used for the signal and they are shifted in opposite directions (very simplistic description but you can get copious details online). The bottom line is that this technique is VERY noise resistant. I say that this is a bit of hair splitting because the problem could still be in the Ethernet subsystem like the interface cards or circuits. Still I think that that while adding a toroid to some things will help, I doubt it will have an effect on the Ethernet cable (but I don't see how it can hurt). It could still be helpful on the motor control lines and physical shielding and good grounding of any and all things that have PCBs is a good idea. Don't forget to check the power supply levels to ensure that you are not getting an unexpected supply voltage drop when you start to push the servos (i.e. draw more current).
 

Reddinr

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#30
Instead of saying "It is possible the ethernet cable isn't the way.." I probably should have said "It is more likely the ethernet cable isn't the way..". It can still happen though so I would not rule it out completely. Even though the signals are differential, common mode signals can be picked up by the pairs and are presented to the ethernet transformers. These tiny transformers are not perfect and can convert some of the common mode into differential mode on the circuit side. It is easy to get into the minutia on these things but from a practical standpoint, some of the techniques I mentioned and Boswell mentioned above can work to solve the issues. Good point Boswell about diff. signals and checking power supply levels. It made me think about a Phoenix Power Inc. DIN rail power supply. It was extremely noisy and caused lots of problems in a system I helped troubleshoot. Replacing the power supply with one with less ripple and noise solved that case. (P.S. Not all Phoenix power supplies are noisy, just that model I came across was noisy.)
 
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