Hello. Thanks in advance.
I have a bullet press that I want to make automatic. The normal way they do this is with a motor that spins a crank shaft type thing that operates the press. but this involves machinery that i just don't have access to. So I am thinking of using some kind of air powered hydraulics or something. I understand the concept, ram pushes up (around 2.5"), Ramp pushes down. but doing so is a bit more complicated. For now im simply looking for some ram's that would fit the bill.
I can get more info when i have an idea on what to share.
thank's. is there a type that a valve switching from pressure to vacuum would operate the cylinder?
I'm also thinking that maybe a cam system might not be as hard as i thought. all it really is, is a circle with 2 holes in it one centered one off centered. if i search the net i might find the math on what math i need to do to know the right distances.
what do you think?
Air and hydraulic cylinders have ports on both ends for the injection opf air to move the cylinder back and forth and you can get electric solenoid shuttle valves that alternately pressure one end while venting the other to shuttle the piston back and forth. One advantage of using an air cylinder is that you can adjust the system pressure to control the amount of force you apply to the bullet pressing. A complete system of this type will require an air supply or compressor and tank, a pressure regulator, the solenoid spool valve, a timer to control rate at which the press cycles the cylinder and appropriately designed mounting hardware for cylinder on your press.
A mechanical cam has a fixed travel distance and as long as the cam driving motor has enough power it will rotate the cam to apply whatever force is necessary to keep the cam rotating, break something or stall the motor. This can be controlled by placing a spring between the cam and the press but this gets to be a more complicated system with several parts.
One thing to keep in mind for whatever method you use is the user's (your) safety when the machine is operating. A finger or hand in the wrong place when the ram is closing can result in a serious injury.
As far as the cam method, others use a clutch, so if it binds up, it will just slip, maybe turn off and alert of the bind, then the user fixes it; removes bad component; then starts it back up.
the mounting system i can fab. just needing help on which components to hook up to get the desired movement.
Can you recommend a site that shows the math needed to get the right dimensions for a cam system? a disk with 2 hols and pressed in bearings should for building it. once i know the sizes and distances.
Which press are you attempting to automate?
As far as the cam design you are requesting, I think with your two holes description your are really envisioning a crankshaft and link design. Is that correct? If so then the math is really simple, the travel distance of the end of the rod is equal to 2x the radial center to center distance between the centerline of the drive shaft, ie disc center, and the centerline of the rod connection on the disc.
As far as the air cylinder design, while it has its definite merits, it does require a number of potentially expensive components.
So I guess I can draw up what i'm thinking for a crank shaft style design and come back to figure out proper measurements.
That works for me. Just be aware that a torque driven crank assembly is like a toggle assembly in that it does not produce a constant force throughout its stroke. It produces its lowest force at the 90 degree point and the highest at the bottom of its stroke. It is also best designed to have a relatively long rod length to crank diameter to minimize this effect in operation.
One thing I have been curious about throughout our discussions is what your basic purpose is for "automating" this one stage of shell reloading. The reason I ask this this that when industrial (manufacturing) engineers discuss automating and operation one of the key items is the "work flow" through the entire process line. In other words, in your case it would how the speed and processes of feeding the shell casings and lead and dispensing of the assembled bullets will be performed so as to match the constant speed of an automatic pressing operation.
My thoughts have been, if you are hand loading and unloading the components wouldn't a foot pedal press operator work just as well without having to deal with the constant set speed your current concept.
i have built a bullet collator that will feed the machine. It should be able to feed it much faster than it will operate, ill have some kind of sensor or switch to turn it off and on to keep the feeding tube full. Which is a typical setup for commercially available machines. that should be pretty easy to make
I'm having trouble figuring out what size motor I need. Mainly, because I do not know how. *chuckles*. with the setup in the image I am getting 30 pounds on the end of the lever. While the machine strokes 4.6 inches, it only does work for about the last .5 inches.
(link is a video of the machine in operation, just posted on facebook)
Last edited by birddseedd; 09-05-2017 at 09:18 AM.
The mechanism you show resembles the Star sizer. Study the power driven model for ideas.