How to Calculate Cutting SAM?

Question: How to calculate SMV in the cutting section? ... asked by Mehfuzur Rahman
                  Please tell me how I can calculate SMV for cutting department. ... asked by Ahmed Imtiaz

OCS's Answer:

Cutting SAM can be determined in the same way as you calculate stitching SAM of a garment. In cutting SAM calculation, consider cutting room sub-processes such as spreading, marking, cutting, fusing, re-laying, re-cutting, sorting, numbering and bundling as operations. Whether you like to determine only cutting SAM or all other processes also will depend on you. I have explained procedures for finding SAM for all cutting processes.

The important thing, in the cutting process determining SAM of a single piece, has no meaning when cutter cuts parts of multiple garments at a time. Whether cutter cuts 10 plies or 100 plies using straight knife machine cutting time will mostly remain same. Primary variables in determining Cutting SAM are layer number in a lay, number of markers in a lay.

To determine standard minutes for cutting jobs I suggest you to go for time study of cutting operations, instead of using MTM2 database (synthetic data).

Determine SMV of each cutting tasks using the method explained in how to calculate SAM of a garment

  1. Do cycle time of Jobs (time study for 5 – 10 cycles) 

  2. Do performance rating ( Assess how fast or slow the operator doing the job in 1-100 scale) 

  3. Calculate Basic time (Basic time = cycle time X performance rating) 

  4. Add allowances (machine allowance + personal fatigue) 

  5. Calculate standard minutes (SAM = Basic time + Allowance percentages)


Spreading SAM

Conduct time study and measure cycle time for fabric spreading. Convert cycle time into standard time. Spreading time will vary depending on layer length (and/or number of markers) and type of fabric. To be specific record spreading SAM based on lay length and fabric type. Also record number layer-man involved in layering. Once you have standard minutes for spreading of a layer, you can easily calculate total time required for spreading a lay by multiplying number of layers in a lay. Refer to the following table to record spreading SAM.

Table 1: Spreading SAM record sheet

Sq. no.
Style No.
Fabric
type
Lay length
 (meters)
Marker
size
No. of layer man
SAM/layer
#1






#2







Marker making SAM

Maker making required few minutes and compared to other cutting processes this time is negligible. In case you need to determine marker making SAM and want to add in total cutting SAM, I am showing you how to do it. If CAD marker is used then do cycle time of lying of the papermaker on the lay and fixing the maker with gum tape.

For manual marking determine standard time through time study. In manual marker, making time varies depending on garment components, garment size and a number of markers. Record the number of persons involved in marker making. Refer to the following table to record marker making SAM values.


Table 2: Marker making SAM record sheet

Sq. no.
Style No.
Garment size
Marker size
Total components / size
SAM/lay
No. of marker man
#1






#2








Cutting SAM

Conduct time study for cutting operation. Total cutting time of a lay will depend on garment components, linear length to be cut for garment patterns, marker size, and type of fabric. Cutting time also depends on cutting equipment. Record time study data in the following table. Study cutting time for all sizes in a lay and find average SAM. Cover all sizes in time study. Create a database of cutting SAM with the different combination of cutting for future use.

Table 2: Cutting SAM record sheet

Sq. no.
Style No.
Fabric
type
Marker size
Total components / size
Lay length (meters)
SAM/lay
SAM /
Garment
#1







#2










Fusing SAM

Set temperature and pressure of the fusing machine for a certain speed of fusing belt. You can do here reverse calculation. Instead of time study record operator speed for placing cut components (to be fused) in a minute. Once you get production per minute you can SAM per garment (based on number of fused components) by using formula 1/no. of parts fused per minutes.

Re-cutting SAM

Re-cutting is also done by other equipment such as hand scissors or band knife machine than straight knife cutting machine. Follow same procedures of determining cutting SAM for re-cutting SAM. For re-cutting process, SAM can be presented per lay or per garment. Also, consider whether all components need to re-cut or only a few components.

For the other cutting room processes like, Sorting, ticketing, and bundling determine SAM as per unit as mentioned in the following table.

Table 4: Units for presenting SAM of cutting processes


Operations
Units for cutting operation SAM
1
Spreading
Calculate SAM per layer.
2
Marker making
Manual marking: Calculate SAM for each marker.
CAD marker: Calculate SAM per lay (Cut)
3
Cutting
Calculate SAM per marker. 
4
Fusing
SAM per garment
5
Re-cutting
Re-cutting SAM can be calculated based on the number of layers cutter cut.
6
Sorting
Calculate SAM per marker
7
Numbering/ ticketing
Numbering SAM can be calculated per garment. For that first, find SAM per component and later multiply how many components are numbered
8
Bundling
Calculate Bundling SAM per marker


In the above tables, you collect SAM of different processes in different units. All these standard minutes will help you to determine cutting room capacity or you can calculate how much capacity (standard minutes) you will be needed for an order. 

Initially, you need to collect standard time for all cuts to create a database. Once you have created a database with the different combination of lay length, marker size, garment sizes you can use SAM from your database for future styles.

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