All MetalShaping

Go Back   All MetalShaping > General Metal Shaping Discussion > Basic questions and answers
  Today's Posts Posts for Last 7 Days Posts for Last 14 Days  

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 11-07-2017, 10:57 AM
Ivan Dozzy Ivan Dozzy is offline
Member
 
Join Date: Nov 2017
Location: St-Petersburg, Russia
Posts: 19
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
__________________
Ivan Dozzy
Reply With Quote
  #2  
Old 11-07-2017, 11:23 AM
Kerry Pinkerton's Avatar
Kerry Pinkerton Kerry Pinkerton is offline
Administrator
 
Join Date: May 2009
Location: Near Huntsville, Alabama. Just south of the Tennessee line off I65
Posts: 8,321
Default

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.
__________________
Kerry Pinkerton
Reply With Quote
  #3  
Old 11-07-2017, 11:38 AM
toreadorxlt toreadorxlt is offline
MetalShaper of the Month August '15 Jan '17 Dec'17 Aug'19
 
Join Date: Aug 2011
Location: NH
Posts: 590
Default

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.
__________________
Steve
Reply With Quote
  #4  
Old 11-07-2017, 12:04 PM
Ivan Dozzy Ivan Dozzy is offline
Member
 
Join Date: Nov 2017
Location: St-Petersburg, Russia
Posts: 19
Default

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.
__________________
Ivan Dozzy
Reply With Quote
  #5  
Old 11-07-2017, 02:48 PM
Richard K's Avatar
Richard K Richard K is offline
Member
 
Join Date: Nov 2010
Location: Minneapolis, MN or On the Road
Posts: 1,131
Default

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.
__________________
Richard K
Reply With Quote
  #6  
Old 11-07-2017, 05:31 PM
Richard K's Avatar
Richard K Richard K is offline
Member
 
Join Date: Nov 2010
Location: Minneapolis, MN or On the Road
Posts: 1,131
Default

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.
__________________
Richard K
Reply With Quote
  #7  
Old 11-07-2017, 08:56 PM
Metlmodr Metlmodr is offline
Member
 
Join Date: Nov 2009
Location: Adelaide South Australia
Posts: 93
Default

Am I seeing this right, looks like the material is thicker than his 1mm clearance between dies!
__________________
Kym
Reply With Quote
  #8  
Old 11-08-2017, 02:14 AM
John Buchtenkirch John Buchtenkirch is offline
MetalShaper of the Month October 2012
 
Join Date: Jul 2009
Location: Glen Cove, Long Island
Posts: 1,675
Default

Did you check your hit point with black drain oil ? It should look like a 150 to 180 degree smile a ¼” to 3/8” in front of the raised thumbnail. Those dies are marking up the panel badly. ~ John Buchtenkirch
__________________
John
Reply With Quote
  #9  
Old 11-08-2017, 09:06 AM
Ivan Dozzy Ivan Dozzy is offline
Member
 
Join Date: Nov 2017
Location: St-Petersburg, Russia
Posts: 19
Default

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.
__________________
Ivan Dozzy
Reply With Quote
  #10  
Old 11-08-2017, 09:30 AM
Richard K's Avatar
Richard K Richard K is offline
Member
 
Join Date: Nov 2010
Location: Minneapolis, MN or On the Road
Posts: 1,131
Default

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.
__________________
Richard K
Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump

All times are GMT -5. The time now is 05:35 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.