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Eagle Carrel Tube Bending Innacuracy

Dear Sirs,

We would like to hear from companies and individuals that have experience with the Eagle/Carell tube bender UNI 60. Our company last yeart were split between the decision of qcuiring an Ercolina or a Carrel bender. Both claimed similar features and we chose the Carell for its lower price within our budget at the time.

We have invested in the machine, plus special dies for aluminum tubing and the indexing table, a fair amount of money for our small company. We needed the indexing capability in order to make multiple bends on the same workpiece at different planes. Also the table has linear stops very important. We also picked the digital read out option.

We made the investment in this equipment, over the mechanical bender we had, because we needed productivity and accuracy. We bend aluminum tubing only with OD from 1" (3" CLRadius) to 2" (7" CLRadius) and wall thicknesses between .058 to .083". We use mostly 6061-T6 alloy.

The problem is that this machine is off in degree +/- 2 degrees (4 degree range). When we contacted Eagle Bending, first they were very responsive and send us a new board as they were sure that would be the problem. Also they made us check teh power source while other machinery was operating and that was fine. When we replaced the board, it did not solve the problem.

When we called the company again explaining the situation, their answer is that the machine is only good within that range, that we have to live with that and that if we wanted a machine within a 1 degree range we would have to purchase a bender which would have sensors for spring back and that would be a lot more expensive.

So why we hve a digital board with a 1 degree accuracy? Why our mechanical bender seem more consistent them that? Why now we are stuck cold forging 85% of our bending jobs here after QC...

Help!!!

Paulo

Reply to
Paulo
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6061-T6 is extremely inconsistent in its properties. The aging processes is exactly that: it gets harder as it ages. The result is that variation from stick to stick is significant and batch to batch is very significant. The manual benders may appear to be more accurate due to operator intervention, something that does not happen on a CNC machine.

Springback on mild steel tube of the same dimensions is on the order of 1/3 that of the aluminum. You might want to try a sample run of steel tube to isolate the issues to aluminum or bender.

With those bend radius's and wall thicknesses, you should be us> Dear Sirs,

Reply to
Roy J

Thanks Roy,

We will make some tests with Steel. I hope you are right. The funny part, is that not only out of the same batch and even the same sticks seem very inconsistent. We will also try a T0 temper and hopefully that will work out better.

What I don't understand is that both Ercolina and Carrel claim that their benders are accurate within 1 degree. We will also try to contact current owners of both equipments to see what their experiences are with these machines.

Thanks Again, Paulo

Reply to
Paulo

Most of the newer benders I have seen will repeat within 1/2 degree or so, some better than that. As they get older they get looser but they still repeat to the same point(trying to get that point to be the RIGHT point is a pain but that's a different issue)

I have seen T6 material that had 6 degrees of spring back. If the bender holds 1/2 degree and the material needs 6 degrees, the material is 12 times more likely to be the problem.

Using some T0 material will tell all. Run as many pieces as you can afford on one setup (10 to 20 pieces minimum), accurtely measure the angle (+/- 1/4 degree range), plot it as a histogram, use Excel to give you a standard deviation. SD should be around

1/2 degree on dead soft material. You might also want to program the machine to stop at the end of the stroke, accurately measure the angle it stops at. (1/4 degree accruacy)

You really need to read up > Thanks Roy,

Reply to
Roy J

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