Rules for edging calculations
Calculation of core size - The core size is the size of the core material as it appears in the finished part.
Core length = finished size - thick W1 edge - thick W2 edge
Core width = finished size - thick L1 edge - thick L2 edge
To establish the thickness of each edge the program looks for the edging code in the edging library and reads the thickness. If the function code for the edge is 4 or 5 (post formed) the program uses the thickness of the face code instead.
Calculation of core cut size - There is an important difference between core size and core cut size. The core cut size may be larger than the core size by the amount of the core trim (core oversize). The core trim allows for cutting the core material oversize on the saw to allow for later trimming after laminating, or during edging.
Core cut length = core length+core trim of W1 edge+core trim of W2 edge
Core cut width = core width+core trim of L1 edge+core trim of L2 edge
To establish the core trim of each edge the program looks up the appropriate edge code(s) in the edging library and reads the core trim value.
Calculation of edging pieces -The calculation of edging sizes applies for edge function codes 1, 2 and 3.
Function code 1 is for tape and this is given as a total linear requirement for each different edging material.
Function code 2 is for solid wood pieces; this is calculated after optimisation, and is stored in a picking list called Pnnnnn.PNL where nnnnn is the run number.
Function code 3 is for laminate pieces; this is calculated during the Cutting list operation and stored in the new cutting list.
Function codes 0, 4 and 5 indicate other processes; there is no edging to be calculated.
To calculate sizes the program takes each part edge in turn, L1, L2, W1, W2 and reads the appropriate edge code in the library.
In addition depending on function code the program does the following:-
0 - No edging
1 - Calculate linear edging - normally tape
The width is part of edging description so is not calculated. The results are shown in the edging summary.
2 - Calculate edge size - normally solid edge
Result stored in picking list.
3 - Calculate edge size - normally laminate strip
Result stored in cutting list
4 - No edging
5 - No edging
Calculation of laminate sizes The calculation of the laminate size is:-
lam size = core size + core trim + overlap
This ensures that where there is a core trim there is sufficient laminate to overlap the core.
Core cut length = Core length + edge over trims
Core cut width = Core width + edge over trims
Lam length = Core cut length + length overlap
Lam width = Core cut width + width overlap
For each edge:-
If edging type is postform or bull nosed
add material thickness of core material
If edging type is postform
add postform overlap to front laminate
If edging type is bullnosed
add bullnose overlap to front laminate
subtract bullnose overlap to back laminate
This ensures that where there is a core trim there is sufficient laminate to overlap the core.
The laminate code must be valid and the edging function for this laminate must be 3. If edging function is 0,1,2,4 or 5, the program does not calculate a laminate size. Codes 1.2.3
For every edge the program adjusts the length or width of the laminate by the thickness of that edge. For example, for edge L1, it considers the thickness of edges W1 and W2.
For a bullnose and postform edge the core trim is not added to the laminate size. This is because, for postforming, any core trim is always taken before laminating and the laminate size does not need to allow for the core trim.
Note - for square edge parts the core trim is often taken after laminating so the amount of laminate needs to allow for the core trim and for bullnose edges the size of the back laminate needs to allow for bullnose.
