how much would you charge to make this?

[beanbag]

Or alternatively, how long would it take you to make one of these:






Dimensions are in inches.
Material is plastic
Piece has a trench and square pocket on one side, and a cross shaped trench on the other
Yes, you have to radius all the corners.
You'd be given oversize stock, which you'd have to face down to the correct thickness. The stock is wide enough that two pieces can be fit together with some space between them.
Make a dozen or more from available stock.

I figured it'd take me about 30 min each on my non-automatic tool changing cnc machine, but more likely it will somehow manage to take twice as long.

[Black_Moons]

im thinking you should be able to make some kinda fixture, maybe locating the stock by those 6 holes (a simple jig to locate the raw stock and drill the 6 holes then swap to next jig) to hold the stock in a way that you could freely mill everything while its still supported (a clamp peice ontop of it with bolts through some holes and and dowl pins for alignment on others) and mill both parts per chunk of stock without any dialing in, and flip and repeat.
do one operation on masses of stock at a time if your fixtures allow you to swap stock faster then tools.

[beanbag]

yeah, I was thinking of making a fixture and adding that to the total cost.
Sometimes I wonder if it is faster to swap tools or swap parts.
The other day, I had two vises on the CNC machine, and while one part was cutting, I was switching out the other part. I'm like the Quentin Taratino of CNC machining... Or was that John Woo? Its that guy who likes to make moves where people use two pistols at once.

[Pete F]

Originally Posted by beanbag

I'm like the Quentin Taratino of CNC machining... Or was that John Woo? Its that guy who likes to make moves where people use two pistols at once.

That would be John Woo. They are both kind of awesome, though.

-Pete

[JoeFin]

2nd Op Subplate fixture - 2hrs

Part - 20 min each

Yep I don't get a lot of jobs. Some may want to eat the cost of making 2nd Op fixtures and hope the customer gives them an order large enough to warrent eating the cost. I prefer to give quotes in cost per 1 item, cost per 10, cost per 100

[Carld]

If your using a CNC why would you have to use a fixture? You should be able to work off home for each side and locate the part in a vise or clamp it down with locating stops. One side and one of the through slots in the pocket end should locate the opposite side after on side is cut. Drill the holes first and then mount them on a plate with locating pins if you want to make a fixture then you could do the outside and all other cuts without interference.

Since I don't do or have or want to have a CNC I can't help you on the time to do it.

Remember to apply the KISS method for anything you do.

[bobw53]

I'd do that all in a vise, especially if the stock is a bit thick. Soft jaws on the second side. You didn't give tolerances or type of platic, which can mean a lot. Assuming +- .010 on the features, +-.030 on size and maybe .005 on the holes, I'd shoot for $50 a piece for a dozen of them. Down to $25 for a good customer.

Don't forget the deburring, most plastics are usually miserable hell on burrs(not big, just hard to get off and make it look good) Running a nice sharp new mill drill/chamfer cutter around every edge you can will save a lot of frustrating deburring.

This is the trick of it, you shouldn't be asking how much we would charge, you should be asking yourself, "what will the market bear". What does your customer do? Are they tossing them in a bag and sending the off to the gov for $400 a piece or is it a part in a low profit whosamajig? Are you there go-to guy, or are you trying to get in the door?

Regardless of what it is, we've set a $250 minimum for anything that goes on a machine. Whatever you do, don't give it away.

[Mark Hockett]

I think your estimate of 30 minutes to machine each one is pretty close. You would need to add fixture, set-up and programing costs to that. I would build a simple flat plate fixture with expanding studs that would go into the 6 through holes. That way you can machine both sides with the same fixture. You start by drilling the holes in a vise on all pieces. Then set up the fixture and do the next two operations. If you are doing a bunch make the fixture so it will nest two parts on one plate. Doing that way you would cut the perimeter on both and the front side on one and back side on the other, then flip both and cut the other sides.

Here is a sample of a part I am doing today using the same type of fixture,


The studs are just simple 1144 threaded studs with a 1/4"x 20tpi thread. I used a 60 degree center drill to cut the bevel and machined a SHCS to 60 degrees to expand the stud.




By doing it this way there is no interference from clamps or hold down bolts so all top sides can be machined in one operation.

Here is the part I am making,


BTW a machine with a tool changer is not always faster, I can change tools on my CNC mill with no tool changer just as fast as my mill with a tool changer, the advantage to the tool changer is it can run unattended. Here is a video of my mill with no tool changer,
http://www.youtube.com/user/islandte.../0/NpbN1UDwtQM

[beanbag]

I think I can make the workholding a lot simpler if I just double sticky tape or superglue the piece to a larger flat bar. Then I can do all of one side at once.

I don't know much about the piece, but it is probably some doohickey that helps hold something to something else, some kind of commodity or hobby market part that tries to compete with Chinese knockoff. So the piece is not worth very much at all. And that's the problem. A normal person looks at something like this and figures that it is worth like $10 or so. I can get far more intricate pieces of plastic for far less than that. I don't think the customer can resell these parts for very much.

Mark: Nice idea for those expanding arbors. I have to use that for the lathe at some point.

[clutch]

Originally Posted by Mark Hockett

BTW a machine with a tool changer is not always faster, I can change tools on my CNC mill with no tool changer just as fast as my mill with a tool changer, the advantage to the tool changer is it can run unattended. Here is a video of my mill with no tool changer,
http://www.youtube.com/user/islandte.../0/NpbN1UDwtQM

You haven't seen a Chiron or Robodrill most likely.

Clutch