Quick Die Change Systems? 3

[briley47]

Does anyone have experience (good or bad) with an off-the shelf QDC system?

We have 6 punch presses (Minster, Pacific, etc.) and dies of varying sizes. The changeover between die sets averages on 60 minutes. I would like to see this done in 5, and am interested in a few items:

1. Recommended Brands
2. Positives/Negatives of QDC
3. Tips for Cost Justification

Thanks, in advance, for your assistance!

 

[bvasa]

No matter what off-the-shelf system you go with, there are some basic issues that you'll need to address. Most of the presses on which I've implemented quick change have been relatively small, with die sets in the 250-300# range. The off-the-shelf solutions I'm familiar with only address moving the tools on the bolster and automating the clamps. They don't address the bigger issues of adjusting the press and aligning the tools.

Step one - get a copy of a book on SMED - Single Minute Exchange of Die. This will give you a lot of ideas about how to accomplish your goal quickly and inexpensively.

Next, you'll want to survey your die sets for open and shut heights, then calculate which open and shut heights to standardize all your dies to. This will mean adding sub-bolsters, spacer blocks, etc. It may also require longer guide posts on the die sets that were designed for short strokes, if you're using them to compensate for worn gibs on the press ram.

Do the same with your die clamp heights. Again, this usually entails adding spacers to the tooling.

Finally, set up a good kinematic locating system (one side-to-side locator, two depth locators)with common locating points so that your dies can be easily and repeatably pushed into the correct location on the bolster. Again, the book on SMED will cover this thoroughly.

Make sure your die carts are up to the task. For smaller presses, a single roll-around cart with room for 2 dies sets can be fine. For the big stuff, you'll need powered carts with pusher systems. Don't skimp on these if you need them - cheap ballscrews and bearings don't last long.

With the press adjustment issues out of the way, your die changes may already be in the sub 10-minute range. You can add the off-the-shelf pop-up rollers for the lower bolster and the automated clamps to make things easier, but they won't save much time.

Good luck! It's an amazingly frustrating yet rewarding project.

 

[griffengm]

Bvasa is correct but could have gone further.
Either spend some time observing a die change or video the operation. I prefer video because it becomes a benchmark for the improvements.
Start by looking for things that add work without doing anything such as leaving to get tools, fasteners, or dies.
Look at how many times the set up man measures or stops to check an alignment or measurement. Does he need to set stops for the parts or are they already in place? How many different fasteners or tools does he need to complete the set up? Can it be done with one or better yet, none?
Does the set up man know which die goes into the machine before the machine is finished with the last job? Can the die be pre-set and waiting?
SME has a good book, Quick Die Change, that you might want to look at.
Answering these questions will usually yield ample improvment opportunities well before the investment in OTS QDC systems.
Oh yeah, one more thing. Get your set up people involved in this process. You'll be surprised at what they can and will come up with to improve things for very little money.

Griffy

 

[bvasa]

There are lots of details that go into making a QDC program work, and Griffy brought up the most important part - getting people involved. If you can pace the program so that your setup people and operators have a chance to come up with many or all of the ideas, you've established the basis for a continuous improvement program that will really take off.
What sometimes works well is to assemble the folks and present the problem - idle presses don't make money, no room for more equipment but orders are increasing, whatever your situation is. Put it in tangible terms for the operators. Then take away the usual constraints - tell them they can drill and tap for new clamp holes, set up tool storage racks and hand tool boards at each press, make radical changes. Most importantly, they need to know they can try something that ends up not working without fear of punishment, as long as they coordinate it with you.

Giving ownership of the program to the folks working with it can result in even better overall results than just the QDC effort.

Of course, some people are just ornery and obstinate (workers and managers alike), and you'll have to bludgeon those individuals into submission - figuratively, but tactfully. This is the hardest part of the job.
Good luck!

 

[Cincinnatus]

http://www.jitautomation.com/index.html

10 Minutes vs. 16 Hours With TQDC.
August 1, 2003

The basic concept of the JIT production system is to:

Produce what the customer wants;
Deliver when the customer wants;
Meet the expected value and price.
In order to meet the above three basic criteria, the JIT production system must be flexible, reliable and predictable.
The JIT production system must be flexible to produce whatever the customer wants for an on demand basis. There is no inventory to meet this requirement. With TQDC technology, they can change heavy dies (50 tons) in less than 10 minutes. Without “TQDC” technology, the typical North American stamping operation takes one or two shifts (8 hours to 16 hours) losing valuable production time.
According to the Japan Productivity Centre, over 90% of large (over 600 tons) stamping presses in Japanese Automotive Plants are equipped with TQDC systems, whereas we at JIT estimate that less than 10% of the North American automotive plants are equipped with TQDC features.