cost of injection molding?
cost of injection molding?
(OP)
I'm trying to figure out the cost of manufacture a small plastic part, from begining to end. It's a very simple design, basically just a cover, about 2 inches cubed with hollow inside. Can anyone help me find pricing for this. For example, initial costs, small prodition run costs. Any help would be very appreciated.
oaky
oaky






RE: cost of injection molding?
Assuming high impact styrene at $0.60/lb and wall = 0.06 inches:
Part weight is about .05 pounds. Material cost=$0.033
Cycle time is about 20 seconds or 180 shots per hour. At $35 per hour, cost to mold is $0.19. If you have multiple cavities, divide this cost by the number of cavities.
Add more for packaging, shipping, profit.
This is a simple mold. For a single cavity it should cost about $9000. This should include a sample run of several hundred parts. For future runs a setup charge of $250 to $750 per run would apply.
Does this help?
RE: cost of injection molding?
RE: cost of injection molding?
RE: cost of injection molding?
You're the Man! That helped so much.
Yes, my discription of the part is "a bit hazy", but your assumptions were right on. Let me try to discribe it a little better, and see if you can find any hidden costs.
It has to be durable, able to withstand say a 200 lb. person stepping on it, dropping it on cement, things to that degree. With that, would the high impact styrene and .06 in. walls be sufficient?
As for disign, to be more discriptive, the basic shape is a 5 sided cube, but with a rounded top. So it's kind of a cross between a cube and a cylinder. The base being a square, rising up to the shape of a cylider at the top.
It also has to have a small opening at the base, on one side, shaped like a bell or a hat, so a small rope can slide through it.
One last thing, the part will fasten to a piece of thin metal to close the bottom side. I was thinking this could be done with screws running throu holes in the metal and into the plastic. So for this the part would need some sort of studs to screw into. Can you estimate the amount of additional material this would require? Or any other suggestions on how to connect the metal and plastic, and still be able to access the inside?
Anymore information you can give me would be great.
Thanks,
oaky
One last thing, can you explain why multiple cavities would reduce the mold cost?
RE: cost of injection molding?
It does reduce the cost to mold the parts since multople parts are molded in each shot, saving press time.
Other questions/comments: Rounded end is no problem, will reduce amount of material used slightly. Hole in end is no problem. Not sure whether this is what you have in mind...
Strength should be OK.
Bosses for screw attachment of a sheet metal coveer COULD be troublesome. I need to think about this for a while, maybe come up with a good design. This will add to mold cost, material cost, and may effect cycle time. I will prepare a rough drawing of this and get back to you later.
RE: cost of injection molding?
I guess I don't know how to attach something here. I can Email it to you if you give me your Email address.
RE: cost of injection molding?
Regards
pat
RE: cost of injection molding?
Oaky, also bear in mind the enviroment that the part will be in, chemical & temperature exposure etc as this will affect the material selection process as well as loading.
Kieran
www.moulddesigner.com
Patprimmer, did u get my email last week?
RE: cost of injection molding?
I havn't managed to dig out my info yet, but I haven't forgoten.
When I look at the image, and the draft angle, a 250 Kg load(from memory) will generate considerable side force. The shape of the bottom edge of the ribs will be critical. If they can roll over the top edge, and form a bit of a hook to hold the sides of the lower tray in, I am sure that would help considerably.
It does look like a very nice design.
I would expect that there could be some problems with filling the cavity inthe centres of the grid area. with weld line and gas burns a potential problem.
I like the rib around the bottom, as it will partly counteractthe tendency of the sides to shrink in. It also appears to have good radii between the base and sides. This will help reduce the extent of the hot sopt on the inside rad, and reduce the tendency to pull in
Regards
pat
RE: cost of injection molding?
Regards
pat
RE: cost of injection molding?
I agree with you that the 250 Kg load will generate considerable side force especially on the bottom few of the stacked trays. I have created an interlocking form to counter any tendancy to splay. I've also had an analysis carried to confirm that it will perform under all conditions stated and incorporated a few land areas within the grid section for ejectors which should eliminate gassing. My only concern I quess is that Acetal is the correct material for this application and that it will perform as required over the products lifetime.
Kieran
www.moulddesigner.com
RE: cost of injection molding?
Regards
pat
RE: cost of injection molding?
Cheers
Kieran
www.moulddesigner.com
RE: cost of injection molding?
Kevin can help you without breaking the bank!
RE: cost of injection molding?