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Old 11-07-2017, 10:57 AM
Ivan Dozzy Ivan Dozzy is offline
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Default Thumbnail dies on eckold.

Hi.
I have made a thumbnail dies for eckold.
But it's not works. No shrinking.
I can't understand what is wrong.
Wrong dies shape?
Not enought BPM on eckold.

https://vimeo.com/241712606

IMG_20171107_165529.jpg

IMG_20171107_165515.jpg
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Old 11-07-2017, 11:23 AM
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Kerry Pinkerton Kerry Pinkerton is offline
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Ivan, I can't get the video to play so I don't know if part of your problem is technique.

Cass Nawrocki has thumbnails on his Piccolo and says they work.

D 008.jpg

The only thing that looks odd to me is that you have a very large flat spot behind your 'thumb'. Normally that is only about a 1/4 to 3/8" horseshoe shaped area. Your bigger flat spot may be stretching out the shrink.
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Old 11-07-2017, 11:38 AM
toreadorxlt toreadorxlt is offline
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few things...

You're passing the sheet in and out too fast for that slow of a stroke, withdraw slower and you'll see your making get cut in half.

Thumbnail dies like to be told what to do a little, meaning pull down as you withdraw the sheet. You can actually stretch if you lift coming out of them.

Kerry is spot on, theres too much flat behind the thumb... Grind that area down so its about 3/8" or so immediately behind the thumb.


What do the clearances look like between the ramps when shut? I design mine so they get tighter as they get closer together.
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Old 11-07-2017, 12:04 PM
Ivan Dozzy Ivan Dozzy is offline
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Thanks for help.
The dies shape designed and cnc miled with 1 mm ( about 1/32 inch) gap between up and down.
Before shtinking i move down the upper die till it touch the lower one.
I got a piece of rubber on the middle of upper die. Maybe it's too soft and cant give enought power to stroke.

I will grind a flat place and write about results.
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Old 11-07-2017, 02:48 PM
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The hollowed out part on the upper needs more clearance from the thumb on the lower die. Hollow out towars the front. And ease the side edges of the hollow on the upper so the sheet being shrunk can gather up over the thumb easier.
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Old 11-07-2017, 05:31 PM
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That type of die needs to gather the material from the sides on the way in(pushing toward the machine). Then on the way out the tuck or gathered material is crushed. Hence it is call Tuck Shrink.

To check that the material is actually being gathered into a tuck rather than stretched, use a known size of material, say 8 x 8, then run it through thr die and out the rear. Then measure to see if it is a lesser dimension. If so it gathered, if not it stretched.

Gathering has to occur before any shrinking can happen.
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Old 11-07-2017, 08:56 PM
Metlmodr Metlmodr is offline
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Am I seeing this right, looks like the material is thicker than his 1mm clearance between dies!
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Old 11-08-2017, 02:14 AM
John Buchtenkirch John Buchtenkirch is offline
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Did you check your hit point with black drain oil ? It should look like a 150 to 180 degree smile a to 3/8 in front of the raised thumbnail. Those dies are marking up the panel badly. ~ John Buchtenkirch
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Old 11-08-2017, 09:06 AM
Ivan Dozzy Ivan Dozzy is offline
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Quote:
Originally Posted by Richard K View Post
The hollowed out part on the upper needs more clearance from the thumb on the lower die. Hollow out towars the front. And ease the side edges of the hollow on the upper so the sheet being shrunk can gather up over the thumb easier.
The clearance on thumb and hollowed out part should be more than on a flat area. Am i right?
Now i got same clearance 1 mm (.040) in all parts of dies.
On video i am trying to shrink 1.5mm (.060) 3003 aluminum.
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Old 11-08-2017, 09:30 AM
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As John B pointed out, the smile area (just in front of the thumb) is the only area that is tight. If you designed for a .040 between the dies, you have a lot of areas to rework. When the dies are running, stick a narrow 1/4" strip of metal between the dies at various locations. the material should be free everywhere but the smile.
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