I am trying to set up an Excel spreadsheet to calculate how many pieces of
wood I can cut from a larger piece of wood and what would be the dimensions
of the remaining wood, if any. For example; how many pieces of wood
measuring 1.5" square x 2" length can be cut from a board that is 4.75" wide
x 7" length x 3.5" thick and what are the dimensions of any remaining wood.

I would like to be able to input the overall dimensions of a piece of lumber
and the desired dimensions of the blocks to be cut from it.

I'm having trouble coming up with a solution and being a woodworker and not
a programmer, I'm not sure if Excel can be used for my problem.

Any and all help is gratefully appreciated

Hi St Art,

You should be able to do this, as long as you're aware of the physics
involved and account for that in your formulas. This is similar to
calculating the amount of material stock needed to produce a quantity of
parts, -just in reverse. The physics are the same either way. Here's what you
need:

1. 3 input fields for the material stock dimensions. These should be "size,
width, length". How they're used is what's important. For example, "size"
would be the thickness in all cases. So a 12" long round piece of material
that's 1" thick has a size value of 1.000". It's length would be 12.000". It
has no width dimension, as does your example, which measures 3.500" x 4.750"
x 7.000". Your formula needs to be flexible enough to handle missing
dimensions when they're not needed.

2. 6 input fields for the yielded product. These will be the same as the
three in step one, plus a field to contain "cut allowance" for each finished
dimension.

In the case of your example yield product, you will require three pieces
from "length", with a 3.500" x 4.750" x (1.000" -(cut allowance)) piece
remaining. This is the result of putting a cut allowance on "length".
<2.000"+?"

From each of the three cut pieces, you will yield 2 more pieces. Again, this
will leave a remaining size for each of 3.500" x 4.750" x (0.500" -(cut
allowance)).

You then have six 1.500" x 2.000" x 4.750" pieces, each yielding 3 items.
The remaining material from these is six 1.500" x 2.000" x (0.250" -(cut
allowance)) pieces. <in this case, probaly nothing will be left

3. The value for "cut allowance". This is the material consumed by the saw
<or whatever is doing the cutting.

So, if I understand you correctly, you want to know the sizes of each of the
remaining pieces, and the yield, similar to what I've outlined here. What
complicates it is wanting to know the size of 'leftovers'. You should also be
able to play with the dimension order to conclude how to make your cuts,
based on orientation.

How it (should) work:
Basically, you are calculating the volume of the material stock, then
dividing that by the volume of the yield product, with cut allowance where
required, to get the yield count.

Depending on how you input the dimensions for the yield product, it should
calculate how many area surfaces per piece of material stock in X and Y, and
how many depths in Z.

That's pretty much what I do with costing spreadsheets for parts
manufacturing. As I said, what's difficult is wanting to know the leftover
sizes. We don't care much for what's left over since we order the material
stock to yield the number of pieces we want to run. Leftovers are put into a
"shorts" inventory, which gets considered for use before ordering any new
material.

I think you definitely have your work cut out for you. (no pun intended) If
someone has a solution that calculates how many items of a given volume will
fit into a container of a given size, it may be easily adaptable. You could
ask how to acquire it.

Good luck!
GS

Hi GS
I was having trouble visualizing the process but you explained it very well.
as i will always have length, width and thickness on the wood i have, it was
fairly straight forward to work out a process to give me the total pieces
that i can get from a piece of wood. but you're right...trying to figure out
the leftovers will be the hard part...i'll work on it

thanks for your help

St Art

"GS" wrote:

Hi St Art,

You should be able to do this, as long as you're aware of the physics
involved and account for that in your formulas. This is similar to
calculating the amount of material stock needed to produce a quantity of
parts, -just in reverse. The physics are the same either way. Here's what you
need:

1. 3 input fields for the material stock dimensions. These should be "size,
width, length". How they're used is what's important. For example, "size"
would be the thickness in all cases. So a 12" long round piece of material
that's 1" thick has a size value of 1.000". It's length would be 12.000". It
has no width dimension, as does your example, which measures 3.500" x 4.750"
x 7.000". Your formula needs to be flexible enough to handle missing
dimensions when they're not needed.

2. 6 input fields for the yielded product. These will be the same as the
three in step one, plus a field to contain "cut allowance" for each finished
dimension.

In the case of your example yield product, you will require three pieces
from "length", with a 3.500" x 4.750" x (1.000" -(cut allowance)) piece
remaining. This is the result of putting a cut allowance on "length".
<2.000"+?"

From each of the three cut pieces, you will yield 2 more pieces. Again, this
will leave a remaining size for each of 3.500" x 4.750" x (0.500" -(cut
allowance)).

You then have six 1.500" x 2.000" x 4.750" pieces, each yielding 3 items.
The remaining material from these is six 1.500" x 2.000" x (0.250" -(cut
allowance)) pieces. <in this case, probaly nothing will be left

3. The value for "cut allowance". This is the material consumed by the saw
<or whatever is doing the cutting.

So, if I understand you correctly, you want to know the sizes of each of the
remaining pieces, and the yield, similar to what I've outlined here. What
complicates it is wanting to know the size of 'leftovers'. You should also be
able to play with the dimension order to conclude how to make your cuts,
based on orientation.

How it (should) work:
Basically, you are calculating the volume of the material stock, then
dividing that by the volume of the yield product, with cut allowance where
required, to get the yield count.

Depending on how you input the dimensions for the yield product, it should
calculate how many area surfaces per piece of material stock in X and Y, and
how many depths in Z.

That's pretty much what I do with costing spreadsheets for parts
manufacturing. As I said, what's difficult is wanting to know the leftover
sizes. We don't care much for what's left over since we order the material
stock to yield the number of pieces we want to run. Leftovers are put into a
"shorts" inventory, which gets considered for use before ordering any new
material.

I think you definitely have your work cut out for you. (no pun intended) If
someone has a solution that calculates how many items of a given volume will
fit into a container of a given size, it may be easily adaptable. You could
ask how to acquire it.

Good luck!
GS