How many decimals it has to apply to design & build cut-

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How many decimals it has to apply to design & build cut-

Postby AntonioS » Tue Nov 06, 2007 10:06 am

REPEAT at 3 or 4 or 5 decimals places to manufacture the cutting tools.- What is the optimal tolerances to be applied to reduce the time of adjustment in the machine?


We have a cutting machine in line with our FLEXO printing machine. This machine don’t have rotatory dies, it has a flat dies. We want to have exact the same repeat in both machine to reduce at maximum the distorsions and tolerances.

We have planed to use: sleeve + skickyback + print plate per each print product that we will produce in the future with this machine. Therefore, we think that the repeat defined in the printing stations has to be exact the same for design our cutting tools.

Please see below our lineal gap calculation:

GAP CALCULATION BECAUSE OF DECIMALS REPEAT CALCULATION

5 decimals
3 decimals
4 decimals

Repeat per product

Inches
4,55533
4,555
4,5553

mm
115,70538
115,697
115,7046

A) REPEAT OR STEP OF THE PRESENT PROPOSALS
Inches
27,33198
27,330
27,3318

mm
694,2323
694,182
694,2277

B) PRINTING REPEAR FOR 87 TEETH 10DP with 3 decimals
Inches
27,33200
27,332
27,3320

mm
694,23280
694,233
694,2328

A) - B) Gap produced per step or total repetition

Inches
-0,00002
-0,002
-0,0002

mm
-0,00051
-0,051
-0,0051


Progressive gap
a) 100 m = 3.937,01 "

Inches
-0,00288
-0,28809
-0,02881

mm
-0,07317
-7,31743
-0,73174

b) 1.000 m = 39.370,08 "
Inches
-0,02881
-2,88088
-0,28809

mm
-0,73174
-73,17430
-7,31743


c) 2.000 m = 78.740,16 "
Inches
-0,05762
-5,76176
-0,57618

mm
-1,46349
-146,34861
-14,63486


d) 2.500 m = 98.425,20 "
Inches
-0,07202
-7,20220
-0,72022

mm
-1,82936
-182,93576
-18,29358

e) 3.000 m = 118.110,24 "
Inches
-0,08643
-8,64263
-0,86426

mm
-2,19523
-219,52291
-21,95229

Normally the paper reel has 2.500 to 3.000 m (118.110,24") length. So if we don't adjust the paper flux per example after 3.000 m we will have a gap of 8,64263" (219,52 mm) that it means we are going to cut the blanks or product and we will produce scrap.

Our supplier has suggested to apply only 3 decimals for inches measures. But it seams that will have to able to adjust constantly the machine. Please help us to understand this.

Questions are:

1. Is it possible to manufacture the cutting tooling considering four or five decimals places?

2. Repeat defined for the bare cylinder diameter has to be exact the same for the cutting tools. Isn't it? How many decimals is better to be considered?

3. Please indicate the methodes used to adjust this variations during printing production. Give us the list of aditional variables that we have to manage to cut in the correct position.

Thanks

Regards
AntonioS
 
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