The cutting room is where a garment's cost is least often written down. The costing sheet has a
line for fabric and a line for stitching, and cutting is folded into overhead. But cutting has a
shape that stitching does not: part of its time is the same whether the lay is one layer deep
or forty, and that makes the cost per garment depend on how thick the lay is.
Two kinds of time
- Time per lay. Putting the marker on, setting up the machine, cutting around
the pieces, tidying and bundling. It does not grow with the number of layers.
- Time per ply. Spreading each layer of fabric on the table. It grows with
every layer.
The cost of a garment is the total of both, shared by every garment in the lay:
The sum
(lays × time per lay + plies × time per ply) × cost of a minute ÷
garments cut.
A worked example
These figures are made up to show the sum. They are not a benchmark, not a rate and not a claim
about any cutting room. All the inputs are assumptions:
- Crew: two people, a spreader and a cutter, costing ₹600 an hour
together: ₹10 a minute.
- Per lay: 30 minutes.
- Per ply: 1.5 minutes to spread, ₹15.
- The marker: holds 4 garments, so each ply yields 4.
- The cutter can take at most 40 plies in one lay. More than that and the
order is cut in several lays.
One lay costs 30 × ₹10 = ₹300 before a single ply is spread. A ply adds
₹15 and gives 4 garments.
What it does to the garment
- 4 garments (1 ply): 31.5 minutes, ₹315, or
₹78.75 a garment.
- 20 garments (5 plies): ₹375, ₹18.75 each.
- 40 garments (10 plies): ₹450, ₹11.25 each.
- 100 garments (25 plies): ₹675, ₹6.75 each.
- 200 garments (50 plies, so two lays of 40 and 10): ₹1,350,
₹6.75 each.
- 400 garments (100 plies, three lays): ₹2,400,
₹6.00 each.
- 1,000 garments (250 plies, seven lays): ₹5,850,
₹5.85 each.
The range runs from ₹5.85 to ₹78.75, a factor of more than thirteen. Against the
₹640 direct cost in the
costing example, ₹6.75 is 1.1% and
₹78.75 is 12.3%.
Where the curve flattens, and where it does not
The first plies do all the work. Going from 5 plies to 10 saves ₹7.50 a garment; going from
10 to 20 saves ₹3.75; from 20 to 40, ₹1.88. The fixed ₹300 is
being spread over more garments each time, and the saving halves with every doubling.
Past 40 plies the machine limit takes over. A fourth lay brings another ₹300, so the cost
per garment stops falling smoothly and starts to move in steps. At 200 garments, two lays
cost as much per garment as a single lay of 100.
Cut as deep as the machine and the fabric allow
A thin lay spends the same set-up time on fewer garments. If three small orders of the same
fabric can share one lay, one of the set-ups is saved. Whether they can is a planning
question, not a cutting one.
What to do with it
- Time a real lay. Write down the minutes to put the marker on, to cut, and
to bundle, then the minutes to spread each ply. Two stopwatch readings give the whole
sum.
- Group orders by fabric. Small orders in the same cloth cut together
cost less than the same orders cut apart. The
minimum order article and the
sizes article show how short runs lose in
other places for the same reason.
- Put cutting on the sheet. A line for it, based on the usual lay depth,
and a warning on a short run.
What the sums leave out
- A made-up crew, times and limit. All are assumptions. Use your own.
- Fabric. The cost of the cloth lost to the marker is a bigger question,
and the marker planning article covers it.
A longer lay can also change how much fabric is wasted at the ends.
- Different garments in one lay. The sums assume every ply yields the same
four garments. A mixed-size marker changes that.
- Quality at height. A very deep lay can cut less accurately at the bottom.
That is a limit your own cutting room has to set, and it belongs in the 40.
Once you have the cost per garment, put it on the costing sheet with the fabric, and use the
costing calculator for the rest. For the fabric half of the same job
see the fabric consumption article.