most effective solution for automation

Hi PC,

Depends mostly on the type of machine that you have access to. If you want to buy a dedicated machine for this, then that is one thing, but if you have an existing general purpose milling machine say, then making a jig could be the answer.

Make a jig to hold part, then do the one hole first, then do the other with a simple re-adjustment between first and second holes.

How are you doing the holes in the first place? because you could be drilling and countersinking in one action.

Neil

We are going to buy a dedicated machine. The holes are already punched in the strip, the machine will just perform the countersinking operation.

But as I have already mentioned the feeding arrangement of the strips & quick machining of the two holes, are the problems as we want to machine two holes in 5 sec (this time also includes the feeding time, loading time, unloading time)

From this description I assume the strip is prepunched with holes and you need to countersink them. Is that correct? If so, can you tell the strip supplier to punch and countersink in sequence before he trims them to 140MM. You then have the final forming operation to do.

If the description is not what I think, and you have to both drill/punch the holes and then countersink them and then trim to 140 MM and form to shape.

my sheet metal shop can countersink the hole right on the punch press using a special tool.......ask your shop about it

The copper strip is being cut and formed. A die could cut and form it and at the same time punch and counter sink the holes. The metal is soft the die in counter sink it would just displace the metal. The process is less exact as machining.

As usual, the person asking the question has supplied very little information, but expects to receive good, helpful answers.

PC, let me give you a clue, "Garbage In, Garbage Out"! If you want good answers, supply good information. You say the material is copper, but say nothing about the alloy or purity of the copper or its hardness. You also do not say how the suppliers currently send these parts to you, i.e. loose in a box, separated in trays with individual compartments or end-to-end, stacked or nested, etc.

You give the overall length and width, but say nothing about the shape other than it is an extrusion. Some extrusions are handled more easily than others. If possible, get your supplier to stack the extrusions, possible using the punched holes over rods to align them. This could also save space in shipping and storage and cause less damage by nesting the parts. Then they could be magazine fed with an escapement mechanism to remove one part at a time off the bottom or top (if stacked vertically) or off of one side if horizontally stacked (as in a tray). If parts tangle somewhat when stacked, a horizontal vibratory track may help untangle and de-nest them before feeding to your machine.

I once had to automate a valve assembly that included a very light and easily damage coil spring. The parts came from a spring manufacturer stuck onto sticky paperboard. In manual assembly, our operator removed the springs one at a time, trying to be careful not to damage them, but we still had an unacceptable scrap rate for damaged springs. I told the assembly machine builder to plan on gravity feeding the closed end springs via a tubular magazine, then went to visit the spring vendor in a nearby town. His operation was bare-bones and the sticky paperboard was a cheap and easy way to keep the springs from tangling. I asked what would be the result of eliminating the sticky-paper and stacking the springs in tubes. He said he could actually give us a cost reduction. I then consulted with various durable plastic tube extruders and hit upon the right material and dimensions for good feeding. The cost of the tubes was justified by the reduced spring price and reduction in disposable packaging. Shipping cost of returning the empty tubes was nill since the spring manufacturer simply brought some of them back on each return trip after delivering springs.

Regarding the machining operation, check with custom multi-spindle head manufacturers. For light duty machining operation such as yours, small spindles might be located very close together. The head might not be cheap, but if your production is high, its payback time could be short. As you pointed out, and index table machine is also very expensive. A slide jig would be cheap to make, but the doubled machining time could be costly in the long run. You may also be able to use fixed parallel spindles with a friction or cogged belt drive of your own design mounted on a slide, or feed the work piece into the drills, vertically or horizontally.

Another possibility, as others pointed out, is to press (cold form) the countersinks. If the copper is soft and not something hard, like tempered beryllium copper, this could be practical. Then you would get both holes with one punch, and as a bonus, no chips! The disadvantage is that it could distort the dimensions surrounding the hole slightly, but perhaps not outside of product specifications.

Just a few thoughts.

Please next time provide more info. A photo or sketch would be invaluable. As the saying goes, one picture is worth a thousand words.

Here is a little more info.

If you are using 8.5 or 9 mm drills for your 8.5 mm countersink, you will need drill bushings in a bushing plate if drilling together. Because of the 10 mm spacing you will need special bushings. From the Carr Lane Mfg. website's online catalog:

Special Bushings for Close Hole Spacing:

When holes are located close together, special bushings are sometimes required. Thinwall bushings, where the bushing ID is larger than the normal ID range for a given OD, are often a good solution. Holes for thinwall bushings must be very accurate and round, because these bushings are more-easily distorted. For very-close hole spacing, especially with headed bushings, specify bushings with ground flats.

Also, special order bushings such as these can be requested in bearing type materials such as bronze and Oilite (oil-impregnated, sintered bronze) and could work well in a light-duty drill jig. You will have to check if it is possible to find 10 mm drill collets to hold 8.5 mm drills.

My mistake!!!!!!!

well, as u said I should have attached drawing earlier & gave more specs.

Pls note - Only encircled region in the photo is to be machined.

Material of the component - Copper (ETP grade, 1/2 H temper), so there is nothing to bother about hardness.

As far as c'sk on press is concerned, we are already doing it for small size c'sk. But as u see the one we are machining is having bigger dim. If it's done on press machine, it will cause more deformation (bulging on perimeter). This will creat problem while riveting (the c'sk is filled with rivet head) and hence not acceptable. So machining is the only answer.

Now feeding these components through Vibratory bowl feeder is not reliable due to there small thk, long length, offset bend & uneven shape. It will take large size feeder, the feeding rate will be somewhat 8sec per job (we need 5sec per job), & again due to offset bend if one job climbs over the other while moving aling bowl feeder, it won't separate. A highly unreliable business.

For stacking, as u have suggested, even we are working on it. But there is one problem. As I have mentioned, the requirement is 5000/shift (1 shift = 7hrs). And there is a limit to the no of components that can be stacked, this will increase the frequency of refilling the stacks by the worker. So we want a solution for stacking as many components as possible.

We checked for twin spindle drill head of Desouter (with 10mm CTC), which can do the job, but we will need special drills , which is unacceptable. So is there any other idea for accomplishing this machining in smallest time.

A wooden/plastic box/carrier that holds the stacked parts, possibly 200-400 or so per box so the maker of the parts can stack them in the proper orientation. The number being chosen so that the shift of each carrier is a simple task for 1 person.

Why is this made of copper? = a costly metal these days? Does it need the conductivity? Can a point to point wire and washer replace the copper so you can make this of steel?

What are the special drills needed for the Desouter drill head? If they are brazed insert tools I can understand your reluctance. These can be quite costly.

I would think that you could make or buy tool-holders to fit the Desouter drill head, but use conventional twist drills for the cutters and use a jig plate with drill bushings as I showed you in my other posting.

I realize that standard 8.5mm drills would not allow the use of parallel tool-holders. The walls would be too thin even to support a setscrew. Therefore, I would recommend using "reduced shank" drills. These are available in 1/4" shank size and 11/32" drill point diameter, which would give you slightly larger diameter than desired, but diameter could be controlled by controlling depth, as in a general purpose countersinking tool. Otherwise, you could grind the points to a smaller (8.5mm) diameter if you have a tool cutter/grinder machine in your tool shop. There may be equivalent metric tools but I have not seen them in the US. The smallest reduced shank metric drills I have seen had 3/8 inch shanks.

To me this would be the ideal solution. The 1/4 inch shanks could easily be mounted in parallel tool-holders. For the tool-holders, 3/8 (.375) inch stock un-hardened drill rod (suggest O-1 or A-2 tool steel) would do if you must, but 25/64 (.391) inch would give a stronger wall and allow over two full threads versus 1.5 threads using 3/8 stock) for 4-40 x 1/8 inch long setscrews (3/32 inch long may be available). This would allow clearance for two parallel tool-holders (with flush setscrews) on your 10mm (.3937) centers.

Grind flats onto the drill shanks to allow for the longer setscrews and better seating.