Need suggestions for Max Compression
Need suggestions for Max Compression
(OP)
I'm on a project to build a prototype, about 20"H x 10"W x 10"D.
It needs to compress powders into tablets about the size of an asprin tablet, which takes a minimum of 1/2 ton of compression pressure to accomplish.
I need some ideas on mechanisms that don't include hydraulics, but which will give the necessary compression at the compression point. It needs to be run via an electric motor.
I'm thinking of mechanisms along the lines of a worm gear or threaded means connected to the motor which will move a lever on a fulcrum back and forth which is connected to compression area. Any pulleys or gears in between to multiply the forces is fine, as long as it all fits within the dimensions mentioned.
Does anyone have any suggestions? Is there a known maximum mechanical pressure making mechanism already established so I don't need to re-invent given knowledge.
Many thanks beforehand!
It needs to compress powders into tablets about the size of an asprin tablet, which takes a minimum of 1/2 ton of compression pressure to accomplish.
I need some ideas on mechanisms that don't include hydraulics, but which will give the necessary compression at the compression point. It needs to be run via an electric motor.
I'm thinking of mechanisms along the lines of a worm gear or threaded means connected to the motor which will move a lever on a fulcrum back and forth which is connected to compression area. Any pulleys or gears in between to multiply the forces is fine, as long as it all fits within the dimensions mentioned.
Does anyone have any suggestions? Is there a known maximum mechanical pressure making mechanism already established so I don't need to re-invent given knowledge.
Many thanks beforehand!





RE: Need suggestions for Max Compression
Mike Halloran
Pembroke Pines, FL, USA
RE: Need suggestions for Max Compression
Bret
RE: Need suggestions for Max Compression
Mike Halloran
Pembroke Pines, FL, USA
RE: Need suggestions for Max Compression
Don
Kansas City
RE: Need suggestions for Max Compression
Don: Thank you. That's an interesting configuration. What would you say to a dual set up of that, but add opposing rollers somehow?
Bret
RE: Need suggestions for Max Compression
Don
Kansas City
RE: Need suggestions for Max Compression
RE: Need suggestions for Max Compression
http://www.unionmachinery.com/Product.asp?pid=2734
The BB2 was some early Aspirin tableting machines.
RE: Need suggestions for Max Compression
My machine can't have those size pulleys but then for the mass production purposes they're for, that's what's required. If I can press 4 tablets per minute I'd be very happy - even just 2. So a high torque albeit slow motor, would be needed. I need to multiply the force from the torque of the motor to the point of compression somehow.
RE: Need suggestions for Max Compression
If a slow stroke is critical, just use a large gear for the flywheel and drive it with a low rpm gearmotor and pinion. Alternately, it could be a chain & sprocket.
Be careful in your calculations. You will find that the force at BDC is theoretically infinite (!), which can make it tempting to undersize the mechanism. You need to carefully graph what your maximum available force is throughout your compression stroke and add a healthy safety factor.
Don
Kansas City
RE: Need suggestions for Max Compression
If the BDC is theoretically infinite, then that means the flywheel can be small enough to fit w/i my dimensions. That's great news! Now I need to figure out the motor specs. Its physical size, so all this fits into the space, has to be under 5" but can be about 10" long and high torque and should be located on the bottom of the unit to keep a safe low center of gravity. If you have any other suggestions please let me know - and that supplier too.
I'm headed now to the electric motor forum to see what they may suggest.
RE: Need suggestions for Max Compression
Remember that the point of maximum compression force won't be the same as the point of maximum crank torque, since you get an increase in mechanical advantage as you approach the toggle point at BDC. You'll have to do a little trig. and statics.
There will be some angle where you see your maximum torque. You will also get some help from the gear or chain drive. If your ratio is, say, 5:1, then you can divide this maximum torque by 5 to get an approximation of what the motor will see. Also, the shorter the crank-stroke and the larger the bull gear the better.
Most of what you need you can probably get at McMaster-Carr and/or Grainger.
Don
Kansas City