Building a High Speed Punch Press

Nice work, Jim. Curious about one thing. Wondering how you addressed the physics of all the moving parts. At the speed it will operate, the moving parts possess enough mass to be considered in terms of the forces required to accelerate then from a stop, reverse their direction, and as I see a spring return, overcome that additional force. Inertia comes into play and I wondered where the top speed would be when the bounce and float would come into play. Also I noticed as the cam came around, a bit of side motion towards the right. Possibly this could be addressed with a hardened wear plate, or even a fixed bearing to control wear and keep better control of the downward force.

Just my preliminary observations.
 
Thank you Tony.

At that spring rate, about 20 lbs at max compression, the ram tracks the cam pretty well up to about 400 RPM, greater than that, there is some bounce, I have run it up to about 700 RPM and it was still working but a bit noisy. Per the specs, the actual operational speed is 360 RPM, but I did try to design for double that. In actual use, I suspect that it will be operated at < 200 RPM. There is a return spring in the front cover/bearing support that was not installed for the video. It's rate is about double the spring I was using in the test. I just grabbed something out of the spring box for testing. There is also a return spring in the tooling, but I suspect that it's rate will have to be increased. With a 4200 oz-in motor, I'm really just using the brute force method. There is one other small issue, I somehow made an error in the cam design. It was supposed to have a lift of 0.328 and I wound up with 0.480 lift after the third iteration. I didn't catch it before I built it, I don't know how I missed that one. The customer wanted 0.750 so I guess that's a compromise.

I also have some concerns about the lateral motion. Ideally the ram should ride in bearings, or actual ways. The design challenge was not having enough meat in that area to install bearings. When the customer specifies a HF arbor press, and won't budge off of that, well, he gets what he gets. I suspect that the service life of this one is not more than a couple of months. In terms of the number of strokes, this will see more use in an hour, than the average arbor press would see in a lifetime.

I have a new press frame designed that the power head will bolt right into when this frame goes south.
 
I didn't even think of "valve floating" (just an example of the problem that Tony mentioned,) ! Are you using an angled roller follower ? I can't WAIT to see that thing running :)

PS: Weird that your customer specified the lift of the cam. It seems obvious that the material is either soft or thin. Less lift = more mechanical advantage and less wear.
 
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I still don't get the high cam lift though, wonder why ... :)

I developed 3 different cam profiles, and I suspect on the last one that when I drew the circle for the max diameter, I typed in the wrong value and just didn't catch it. It works, but is not exactly what I wanted.
 
I developed 3 different cam profiles, and I suspect on the last one that when I drew drew the circle for the max diameter, I typed in the wrong value and just didn't catch it. It works, but is not exactly what I wanted.

Sure, but why did the customer specify the lift, that still sounds strange to me ? (Ignore if this is proprietary.)
 
The customer wanted 0.750 lift. I felt that was too much after I did the torque calculations, so I told him he could have 0.312, but after generating the first profile, it actually came out at 0.328. I think it will be OK at 0.480. I'll know in a couple of days.
 
Very nice! Are you building the bottom die as well? I apologize if I may have missed that question in this thread.
 
Very nice! Are you building the bottom die as well? I apologize if I may have missed that question in this thread.

Thank you Andre.

No, the die already exists. I do want to build a new one for the customer and clean up some of the design in the existing one. That will be a whole new project and unfortunately I won't be able to post that one.
 
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