HOW TO MAKE AN ACCURATE OPERATION BULLETIN?

 

Introduction

Being an Industrial Engineer (IE). Everyone trying to make an accurate operation bulletin (OB), but often it is not even close to accurate of 60%. In many cases, inaccurate operation bulletins were opened windows to unwanted discussion and arguments. Those arguments end up with further manipulation on OB to conservative zone for work-floor person. Manipulation in operation bulletin is not integrated work, it is a crime. Inaccurate OB and its details lead to inaccurate cost quoting and another end low efficiency. Subsequently, the deliration of the operation bulletin prepared may not solve.

In this article, we review detailly about what are the parameters should be considered for 360-degree analysis to make accurate operation bulleting.         

1. Tech pack and style details

                Tech pack is the primary details from the buyer or designer. Most of the costing SMV is prepared with a tech pack. Because early-stage garment samples might not be ready. Even sample is available, IE responsible to review the tech pack thoroughly. Each and every comment on the sketch has to read and understood well. Based on that samples have to verify. Most of the cases sketch is considered as primary details to verify the sample. If any deviation between the sample and tech pack then IE will have to discuss with concern and get clear to right thinks. Based on the right point OB has to prepare. All points should be considered without missing the process.

2. Product development comments

The Product development comments are given in the style sheet or tech pack. Product development comments are like the Bible Verses to develop samples accordingly. This part will assist IE for understand the garment construction clearly. Samples and Product development comments are to be verified to prepare OB.  

3. Style specification details

It is containing the details of materials about of body fabric, trim fabric, interlining, thread, button, labels, embroidery, printing, applique, and other accessories required in product.

4. Measurement chart

Measurement charts help to understand the size and length of the seams of the garment size-wise. IE could understand the size-wise changing parameters. Small size to big size there will be different in terms of measurement. IE has to read it and understood possible machines and attachments.

Also, this will help to understand the seam frequency, seam distance, needle gauge, Bobbin changing time, etc. There are two major type in measurement chart,

A)      Before wash – Measurement chart – Need to set for actual production line  

B)      After wash – measurement chart - Need to set to achieve in washed garment measurement.

Both have to read well and considered while making OB.

5. Pattern and grading

The primary pattern is developed for base size. This is called a base size pattern. From this graded for anther sizes. Usually, the measurement is tracked with grading percentage. As per the below table, the order has a total of 5-sizes i.e. SX, S, M, L, and XL. In that Size, “M” is the base size. From the base size, other size patterns and samples are graded.  

 

Size	XS	S	M	L	XL
Grading %	-7%	-5%	0	+6%	+12%

Whi  Note: Measurement of Size “XS” = M – 7%,  Measurement of Size “S” = M – 5,  Measurement of Size “L” = M + 6%,  Measurement of Size “XL” = M + 12%

a)  Size-wise changing measurement – Graded

     b)  Size wise constant measurement – No graded size-wise. For example, Cuff Hight, pocket size, front placket width, so on. We have to study it well to suggest the right attachment.

       c)  Special seams like pintuck, smocking stitch, decorative stitch, pattern stitch, etc. are changeable size-wise. This should be checked and accommodated in OB.

6. Buyer and QA comments

Apart from the above paraments, the QA technician and buyer give some comments on the same. Most of the time there will be new addition or modification in the present sample. This should be considered in OB to set accuracy.

7. Comments from sewing (CRM)

Contacting critical review meetings is good practice. The IE who is preparing OB, they have to contact critical review meeting of product and order with floor level technician. They could share a good point to upgrade our OB to the actual setting level. Also, the bottleneck process will be reviewed well early to make simple or easy methods.

8. Fabric content

Fabric content one of the key factors to estimate the SMV. SMV will be vary based on fabric content even for the same process. For example, Sleeve attaching SMV is not the same for Owen fabric and knit fabric. Based on the fabric content some additional process will be added.

Few examples for a different kind of materials and SMV changing factors

a)       Cotton – Quit stable handling, Most of Owen fabric made by it.

b)      Silk – Very sensitive, some safety stitches and special machine setting required.

c)       Polyester – Handing time is higher than Cotton, cutting edge fraying is common. Need some safety stitched and special process for this fabric.

d)      Lenin- Similar to cotton, Need to considered handling and fabric shrinkage or elongation   

e)      Chiffon, Nylon, Rayon - Handing time is higher than Cotton, need some safety stitched and special processes to achieve garment and seam strength.

f)        Spandex – Pressing temperature is restricted. Edge rolled up the chrematistic fabric. 

g)       Wool - Handing time is higher than, weed to increase machine duty. The sewing speed is less and additional handling required. 

h)      Jute – Required special machine and handling.

i)        Lothar – Required special machine and handling.  

 

Note: If a product made with above all different contents, then SMV will not be the same. Each and every fabric content has its own catacaustic. Based on that, the making method and process will vary. The IE who making OB has to check with an expert about the details. Also suggested trail sewing to understand the realities of the fabric in process-wise to make entire garments.

9. Fabric count

the fabric count is highly contributing to fabric characteristics. Based on the fabric yarn count, the fabric characteristic will change. Fabric count measured by warp and weft counting in fabric (or) This also measured by GSM

Syntax of Fabric count

Fabric count construction = Warp yarn ticket x Weft yarn ticket, Warp yarn count x Weft yarn count, 

Example Count =20’sx30s, 120 x 80

Referring to the count of warp and weft, we could understand the fabric construction. Some loose or tight constructions lead to operation behavior changes. IE should be considered about the fabric construction. Could be referred sample swatch if the construction is not able to predetermine or understand. Based on the yar cunt SMV will vary.  

10. Fabric weaving

Fabric weaving type also contributing to fabric characteristics.

i) Few major weaving types in woven 

a)       Plain weave, Twill weave, Satin weave, Jacquard weave, Dobby weave, Crepe weave, Velvet weave, Chiffon weave, Oxford weave, Rib weave, etc.

ii) Few major knitting types

b)       Jersey knit, Rib knit, Interlock knit, French terry knit, Fleece Knit, etc.

   Based on the fabric type, the operation SMV will vary. Required parameters have to consider during SMV calculation.

Note: Weaving itself there will be one-way, two-way, four-way, engineered designs. The same has to be followed during the sewing process. These points should be evaluated carefully to accommodate in SMV,

11. Fabric appearance and pattern

Garment durability is based on the fabric's direction. i.e. Warp direction, Weft Direction, Bias, etc. All the patter mentioned the pattern direction. The pattern direct is considered to achieve a good appearance and quality of garments. But when we making garments, some processes are not the same between each fabric to other. The detail should be considered while calculating SMV.

 Few examples for a different type of fabric appearance.

a)       Solid or plain fabric – Normal and no matching parameters  

b)      Stripe fabric – Trimming, Matching, Mirroring, fabric ways to be considered

c)       Check fabric – Trimming, Matching, Mirroring, fabric ways to be considered

d)      AOP – All over printing – Based on printing type

e)      Engineered Printing - Matching, Mirroring, fabric ways to be considered

f)        Embroidery fabric - Matching, Mirroring, fabric ways to be considered

g)       Bias – Need to maintain grain line in the garment.

12. Thread Type

Garment seam quality is decided by sewing thread. Thread type is a key factor for operation progress. thread count, content, construction, tenacity length, loop formation, linear strength, plies, resist to abstraction, flexible, twisted per inch, elongation, shrinkage, and strength is highly contributing to sewing performance.

For example,

a)       100% cotton thread - Thread breakage rate is Hight, compare with spun.

b)      Polyester thread – Melting and breaking on heat,  

c)       Foment thread – Breakage and handling time is a bit high

d)      Elastic thread – Inconsistency seam formation, often setting adjustment required. Thread breakage also quilts high.   

e)      Highly twisted thread – untwist during sewing and break the thread,

f)        Inconsistence linear – seam defect and thread break, so on

  IE should be check and considered thread type to estimate SMV.

13. Seam and stitch type

A wide range of seam and stitch types used to sew a garment. Followed by fabric and garment construction, seams and stitch type are defined.

a)       Seam type: Double fold, single fold, hemming, felt seam, safety stitch, flat stitch, topstitch, edge stitch, serge, so on.

b)      Stitch type:  Lock stitch, Chain stitch, Zig zag, Saddle stitch, Singe thread chain stitch, 2 to 5 thread overlock, flat lock, blanket stitch, button stitch, buttonhole stitch, hey hole, etc.

Based on seam and stitch type, SMV will vary. Let take an example for side seam, Side seam process could be done with lock stitch, chain stitch, overlock, or flatlock. But SMV will vary based on that. IE has to considered seam type and stitch type for SMV calculation.    

14. FPT – Fabric Pull test

Based on the fabric testing report, some of the processes have to be added or the seam has to be adjusted. This has o review by IE if any point to be considered in SMV calculation.

15. GPT – Garment Pull test

Based on the garment pull test some of the additional layers have to add. Or some special seal stitch has to be considered. IE has to review and consider if any points to be considered.

16. Pre sewing process – Printing, Embroidery,  

Some of the styles containing pre sewing process. For example, printing, embroidery, so on. IE has to be considered while calculation SMV style.

17. On-line Special process – Applique, Printing, Embroidery,

Some of the styles containing between sewing process. For example, applique, printing, embroidery, so on. IE has to be considered while calculation SMV style.

18. Post sewing process – Handwork, Sequence, Applique, Printing, Embroidery, 

Some of the styles containing pre sewing process. For example, handwork, sequence, applique, printing, embroidery, so on. IE has to be considered while calculation SMV style.

19. Product safety

Under the product safety parameter, some of the standard has to be followed in garment manufacturing. For example, button pull test, snap pinch, interlining bond strength, Loop secure, sharp edge, and metal safety, so on. based on that if any workmanship is added then it should be considered in SMV.

20. Order quantity  

Order quantity is a considerable factor to fix the planned efficiency and planned output. For short quantity, we could not plan for a higher level of efficiency or output. Before completing of the learning curve, the order will be completed in production. Same way huge quantity of orders could plan for higher efficiency and higher output. Because there will be production running after the completed learning curve. 

 21. Color combo and color-wise qty

A total number of colors and color-wise quantity also factor understanding adjusting time. At every end of the color, there will be a small change over in thread and a small adjustment in the machine (if required). This factor also to be considered in OB and fixing the target.

 22. Size wise break up

Size-wise breakup qty is a key factor for individual operation performance, some core replacement orders, size-wise quantity is not distributed evenly. There will be higher quantity or lesser quantity is some size. This has to be considered while making OB. If we assumed a girl’s dress with decorative-smocking stitch. The stitch frequency is getting change size-wise. So, we have to consider the size-wise order break-up factor to update OB accordingly.

23. Delivery date

The delivery date is a factor to cross-check planned output. What we have planning in OB that will be followed in production. In some cases, the lead time will be short. In that case, we have to increase the manpower to meet the required rate. In some cases shipment not achieved even after produced 80% of efficiency, which means the required output has not met. So, IE has to read and understand both ways to achieve efficiency as well as the planned delivery date.

a)      Planned output increase ~ Manpower increase; Efficiency is constant

b)      Planned output decrease ~ Manpower decrease; Efficiency is constant

Wise action is to increase or decrease the manpower to meat delivery with good efficiency.    

24. Lineage and number of lines planned

Line age is a key factor for calculating worker efficiency, manpower calculation will be varied based on worker efficiency. If the line and operators are new then we could not get 90% of efficiency. Based on lineage, worker efficiency and planned efficiency should be fixed. The total number of lines planned and line-wise planned quantity also a key factor for fix planned output.

25. Workshop efficiency (or) Section efficiency

Section efficiency is the key factor to understand the skill set and achievable efficiency. For example, the sewing sections with 10 lines was achieving an average of 70% efficiency. Util with proper cause, this section could not plan lesser than that which lead to idle time. Another end couldn’t plan 90% On average which is very tough to reach 70% to 90%. The operation bulletin parameters should be planned for continual improvement of the section and factory. In this moto referring section efficiency to make OB is important.  

26. Required rate of efficiency and output

The required rate of efficiency and required rate of outputs are not the same. Efficiency could be achieved even with available manpower. But the required rate of production to meet the delivery is not. So when we fix the planned output, the required rate should be considered. Another end there should be clearly understood in production shop abut unit efficiency. This is an ancillary point to be considered in OB.    

27. Machines

When we estimate SMV for a process, there will be options for different machines. By the type of machine and its application, SMV will be varied. For example, patter sewer and manual machine attaching will not be the same SMV. Some of the machines facilitated with additional attachments i.e. back puller, auto trimmer, auto excess trimmer, auto stacked, side slider, auto back take, so on.

Based on the option using in the machine, the process SMV will have to estimated. 

28. Seam frequency and grading

Grading details is essential for assig right attachment. Followed by measurement and grading details, Folder input size, folder output size, Margin details, no of rows for pintuck, no row for decorative stitch, placement details, placket width, etc. considering details help to provide appropriate attachments and SMV in OB.

29 Right machine and accessories:

Operation bulletin should be stated with clear details about machine type, Pressure foot, attachment, sewing aids, templates, etc. process-wise. often observed the SMV of OB and actual SMV are not the same. Due to not using the right machines and accessories for the particular process. Considering the right machines and right attachments will assist to estimate accurate SMV.

30. SPI – Stitches Per Inch

How many stitches stitched per inch is called SPI (stitches per inch). Stitches per inch are a factor that contributes to sewing time. We considered RPM as content and If the stitches per inch increase then sewing speed will be reduced. Else if stitches per inch are reduced then the sewing speed will be increased. So SPI also a considerable factor to estimate SMV.

31. RPM – Revolution per minute 

Revolution per minute is used to measure machine sewing speed. How many stitches could the machine sew per minute is called RPM? Some of the machine RPM is limited and could not increase. And some of the processes could not drive the machine at high speed. Some f materials not suggested to drive fast considering material safety. While calculating SMV, RMP should be considered.

32. Additional setting

Considering some of the setting and option will help us to improv the effeteness of OB.

Few examples (a) Auto back tack – can be reduced handling and pedal motion and time by setting auto back tack. (b) XY Stitching- Some basic programs help to reduce the sewing time. (c) E-Prom can be maintained quality will less SMV, (d) Auto trimming, (e) Auto thread cut, (f) Pattern sewer, (g) Profile sewing, (h) Die-cut, (i) Hot drill, (j) Laser light marking, (k) Fuse press, (m) Heat transfer, (n) Folder press by fuse, (o) Hand iron, (p) Auto zig machine, so on.  

33. Methods of Process,

Choosing the right method is key to achieve the planned efficiency. Before denoting method details in OB, the method should be check and verified. Considering inappropriate methods (or) unpracticed methods has become critical to the production line. Often observed some of the good methods end up with drop as not given required training to operators and concerns. So Operation bulletin should be contained testified methods. 

34. Machine and attachment

Planned output considered many parameters, i.e. required rate, break-even, No of employees, order qty, etc. Planned efficiency is the primary key and planned output is a secondary factor. It has to adjust well for better line balancing and global efficiency.

35. Planned Efficiency,

Planned efficiency is not a single factor, It has arrived from other factors of workers efficiency, organization efficiency, leaning curve type, lineage, line balancing, the skill set of employees, Work content of the style, order quantity, so on.

The logic of planned efficiency is,

Organization < Planned efficiency < Worker efficiency   

Planned efficiency should be in between the organization and worker efficiency. If we planned higher than worker efficiency then it is no logical.

36. Workstation

No of workstation calculation is not only based on OB, It is about the physical line size. For example, if the line has 40 work station, and the style required 20 workstations. In this case, the line could be planned as Line A & B with two output. Simply adjusting to 40 workstations will affect the line efficiency and workers' utilization. In other cases, if the stye required 75 workstations than con increase to 80 workstations along with planned output. Two-line can be combined for one output.

37. SMV,

Process wise SMV is to be double-checked. Calculating accurate SMV for every individual process is enabled to get accurate SMV for the style. While we using Pro SMV, we have to check correlation and deviation. After fixed deviation and make it accurate, then updated SMV could be used in OB.  

38. Pitch diagram,

A Pitch diagram is a tool to understand the operation bulletin effectiveness. The actual pitch diagram is used in the production floor with the actual cycle time. Here, we taking SMV instead of actual cycle time to get the pitch diagram. The pitch diagram can be enabled in the OB sheet itself. Based on the pitch diagram, we could identify the bottleneck process and underutilize the process. Followed by this we could plan for balancing.   

39. Key process for the learning curve,

OB should be mentioned clearly about key processes where it is required training in advance. So that particular process can complete the learning curve time to feed the next process.

For example

Process (P)	P1	P2	P3	P4	P5
Skill Level (s)	C	B	A	B	B
Learning time	2 Hours	4 Hours	5 Hours	4 Hours	4 Hours

Process => P = {P1, P2. P3, ….}

Skill required for the process => S = {A, B, C, D, E}

Learning time for C Skill Operator => LT = {1, 2, 3, … n}

If the operator is C Skill to the process, then we have to check the training required.

Based on the training required hours, advanced training should be arranged.

For example, P3 has required 5 hours of training, So the IE could advise in OB for 4 house advance training.

40. Pull system,

In the flow process, there should be a pull system from the last process to the first process. This is possible by splitting workmanship accordingly. Let us assume the capacity keeps increasing in over the process, then there will be a pull system. Let us assume operates A, B, C, … N.  worked sequent.

Let assume,

Operators = {A, B, C, … N}

Capacity of operator = {Acp, Bcp, Ccp, … Ncp}

Pull system = Acp < Bcp <Ccp, … <Ncp

This system could be used in a lean layout like move back-to-back. Pull back side operators to meet their requirements.

41. Push system,

In the flow process, there should be a push system from the last process to the first process. This is possible by splitting workmanship accordingly. Let us assume the capacity keeps increasing in over the process, then there will be a pull system. Let us assume operates A, B, C, … N.  worked sequent.

Let assume,

Operators = {A, B, C, … N}

Capacity of operator = {Acp, Bcp, Ccp, … Ncp}

Push system = Acp > Bcp > Ccp, … > Ncp

This system could be used in modular kind of layout, lie supermarket concept. Push to clear the work in progress between operators. 

42. Smooth flow,

Once completed the operation bulletin, check the takt time and SMV weightage. There should not be more deviation between SMV weightage and talk time. Workmanship divided and manpower allocation should be distributed evenly.

43. Layout

The layout also affecting the garment SMV, for example, if the line layout is the conversational type with bundling system, then bundle handing time (BHT) should be considered. Or the layout is conveyer system and panel and parts are moving in conveyer, then pick up and dispose of time will be reduced. Also, the bundle handling time will not be there. If the line layout is made for single pieces flow, then there will not be bundle handing time. Based on layout type, the process cycle time and SMV will be changed. The same has to be considered in SMV calculation.

44. Total SMV

Once completed OB, all processes, and their SMV have to recheck to confirm all are correct. Check one by one process and ensure there is no additional or missed in the operation. Once all operations are correct, then check SMV values in every individual operation. And check and formula and total SMV. Also, cross-check with a similar style whether the details and values are close to that.

45. Planned output 

Verify with breakeven cost and breakeven output.

46. Planned efficiency

Check and ensure it is above break-even and realistic with section efficiency. If break-even efficiency is higher than section efficiency subsequently leads to no profit.  

47. Pieces per machine

Check and ensure break-even, Pieces per machine is a key indicator if they add or reduce the machine, the target also will be changed. For example, the target pieced per machine is 25. if a sewing section adds 1 machine, relevantly 25 pcs will be added in the target. 

48. Pieces per manpower 

Check and ensure break-even, Pieces per manpower is a key indicator if they add or reduce the machine, the target also will be changed. For example, the target pieced per manpower is 20. if a sewing section adds 1 manpower, relevantly 20 pcs will be added in the target.

49. Line balanced 

Check the total workstation required and planned. If some of the operations can be clubbed to gather, then give a clear note on OB. A well-balanced OB can help to avoid the bottleneck process during the production run.

50. Summary of Machines 

Cross-check the summary of machine and total manpower required. Process-wise machinery required and the total machine should be the same. if we combine one operator for two processors one operator for two machines, then it has to be updated accordingly. Some of the special machines should be given with remark. so that the production team could take special care to arrange them. 

51. Summary of manpower required 

Cross-check process by process manpower calculated. Allocation of lesser manpower may lead to a bottleneck process and subsequently become a critical process. Other end allocation more manpower cause for operator idle.

Conclusion

Operation Bulletin should be considered 360 degrees analyzed details. Considering maximum and relevant parameters assists to prepare an accurate operation bulletin. The same can be testified and proven. This kind of operation bulletin and its details always will be acceptable.

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