Waste removal from die cut pieces

[davarino]

Die cutting from steel rule dies is a pretty straightforward process to estimate in terms of presswork. It's pretty much figure how long to make ready, figure IPH, and run with it.

Trim out is also pretty straightforward. Just figure cutting time.

But waste stripping seems to trip up a lot of estimators (including me).

Are there any books or other references that give production standards or pricing guidelines (even if wrong) for waste stripping by hand?

 

[dabob]

davarino . . . are they the same forms? Interior removal or external . . . there are several methods I have seen/done that make it short work . . .

 

[davarino]

No Title

I get different configurations. Interior and exterior removals.

The one that tripped me up most recently was 2M "donut boxes" on 20pt board with some intricate insertion tabs. (See attached sample corner, 2.5" tall on the box edge).

Stripping the waste took "forever" (i.e., 3 hours): they could burst only about 1/4" of material at a time due to the long "tongue".

 

[aqazi81]

For exterior you can use waste stripper from BOBST or some Chinese manufacturers also produce waste strippers. Saves a lot of time.
For interior you can do it on die cutters.

 

[dabob]

I've seen places that used air chisels to help the removal of the exterior pieces . .. they would go through a 3 foot high stack in a very short time . . for interior removal we make a board with the appropriate "holes" to make it easy to punch them through and the pressman does it as they come off the press, about 20 - 30 sheets at a time

 

[davarino]

Thanks everybody! Anyone have any "production standards" info?

As far as I can see, hand processing takes something like about one hour per 2,000 linear inches of 3/8" thick material.* Triple the time on the length of any insets. So a 2 foot stack of 5" x 7" simple, smooth-curve die cut material would take about

2sides x (5 + 7) x 2feet x 32 / 2000 hrs = 1536 / 2000 hrs = about 45 mins
(32 is how many times 3/8" goes into a foot)​

*(In SI units: about 5000 linear cm of 1 cm thick material per hour.)​