Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations KootK on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

TRIANGULAR PERFORATION........ 1

Status
Not open for further replies.

spieagle

Mechanical
Jul 31, 2007
12
Heloo friends,
I want to perforate a 4 feet wide C.R steel sheet with triangular holes, for which i need to make a die.
NOw my question is how to make a die for triangular perforation?.
I have a flat die steel( not hardened) block of thickness 12mm.i have to cut triangular hole through it of dimesion as follows- equilateral triangle of vertices 3.5mm. Thw block is 4.5 feet long and i have to make a double row die and in one row there have to be atleast 80 tri. holes, this block is to be used as a die.
Kindly suggest how to make such an hole in sucha thick metal block what tools to be used?
 
Replies continue below

Recommended for you

Harden it, grind it true, then find someone with an EDM machine and contract them to cut the holes.

Note: Ask them to cut the straight land, _and_ the back taper for slug clearance.





Mike Halloran
Pembroke Pines, FL, USA
 
I agree with Mike EDM is the way to go, but use wire erosion rather than die sinking both methods are sometimes called EDM.

I would speak to a press toolmaker as perf tools soon build up tonnage so consider doing the holes in a progression set up and staggering the punches also a 4.5 foot die only 12mm thick is not a good practice with the forces involved and will be very prone to cracking. Any radii you can put on the tips of the triangles will help.
 
Thanks don , mike and ajack for your valuable suggestions.
your advice and suggestions helped a lot.
 
You can't get a perfectly sharp vertex on the punch or die to pierce a triangular hole. A radius has to be incorporated. The larger the radius the longer the punch life. If you aren't well versed at perforating sheets you may end up wasting lots of money while learning what people in the business already know.

If you are going to be producing large quantities of perforated sheet you need to consider how you will sharpen the die plate. Also consider how you are going to repair the die block when something or someone screws it up. I would consider inserts instead of edm'ing numerous triangular holes. Visit the website of a die component manufacturer to see what type of matrixes and punches you can purchase that have your hole geometry. Dayton Progress is one:


If you have a small quantity requirement look into getting your sheets laser cut. I have had sheets laser cut instead of having a die built. The latest quote I got for getting a new perforating die built was in the $40,000 range. You can get lots of sheet laser cut for that amount.

I suggest you download "The Designers, Specifiers and Buyers Handbook of Perforated Metals" from the following website:


I also suggest that you contact several of the members of the Industrial Perforators Association to see if they already own a die which will produce the pattern you want.

 
thanks dvd for replying. laser perforation is not possible because i dont have the machine. I do have a hard copy as well as a soft copy of "The Designers, Specifiers and Buyers Handbook of Perforated Metals" but it does not have any information regarding the way how dies are made.
And i think $40,000 for a perforating die is toooo much..
i make hardened round hole dies in my factory which costs only $600, i dont know how a die can cost $40,000, and the die which i make dont even crack and last very long.
 
Laser cutting machines are _very_ expensive, which is why you don't have one.

It's also the reason why a lot of shops specialize in doing nothing else but laser cutting; they keep their machines cutting continuously, and that's how they pay for them. Cutting is their only business, and there are enough of them out there to keep the price reasonable.

Quotes are free. Ask.





Mike Halloran
Pembroke Pines, FL, USA
 
My first thought on reading this was to make the the die in (at least) two pieces, probably six. I've just looked in one of my old books (Die Design and Diemaking Practice by Franklin D Jones, 1941) and there is a complete chapter on split, or sectional, dies.

This is gist of the first page:-

Many dies are formed of sections instead of being cut from a solid piece of steel. This sectional construction is employed more particularly for large dies, especially when the form is complicated. There are two principal reasons for using the "split" or sectional die. One is that it sometimes happens that the blanks to be cut are of such a shape that the die can be made more quickly and cheaply than by making a one-piece die. The other reason is that when the required blank must be of accurate dimensions, and there is a chance of the solid die warping out of shape in hardening, the split die is preferred, because it can be much more easily ground or lapped to shape....

 
Thank you Mr. Kapitan for such a good advice, currently we are making the the 4 feet long die in 3 pieces but due to which we are facing allingment problem as the punch plate and guide plate is in 1 piece therefore maxinmum 2 pieces of the die are alligned properly can u suggest if we will split it into 4 or 5 pieces how can we eliminate such a problem.
Thanking you in advance.
 
Kapitan I am nor really sure that 1941 technology is that relevant these days. Wire erosion and modern tool steels have totally removed the problems of dies warping after hardening or making certain areas difficult to machine, so it is certainly not relevant to this particular problem.

There is still an argument to split dies for ease of maintenance and also manufacturability depending on what equipment you have available to you.

To answer your question spieagle the less apertures you have in any one section the easier it is to line up, but you also need to line up more parts. Add to this you will need to screw and dowel each section, which will limit the areas you can pierce in so the tool gets much larger, it is all a balancing act.
 
Well jobbing out for laser may be out of budget.
BUT what is your tolerance of each hole?
Would water jet or plasma work?

Dan Bentler
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor