Pop Quiz! How to order correct quantities of sizes for production

By way of introducing a new head-hurting series (sorry), let’s start with a quiz. If you want to cheat or optimize your chances at acing the quiz, sneak a peek at Size is nothing but a number. You can also review pages 114-120 in The Entrepreneur’s Guide to Sewn Product Manufacturing.  Here’s the scenario:

You want to place an order for style 1001. Style 1001 comes in 2 colorways, white and black. I’m going to give you the order quantities per size -an example that a customer sent me in real life- and you’re going to tell me how to make the marker.

Your crash course in marker making: Ideally, a marker is designed so that all garments can be cut at one time. If that is not possible (this example is not), you plan as few cutting jobs for the customer’s order as is possible because each additional cut is expensive (double, triple, depending on the number of cuts planned). If there is more than one colorway, you can cut them both together provided the cuttable width is the same for each color. In this example, black and white can be cut together. Lastly, you want the longest possible marker because each fabric layer or ply must have a 2″ buffer on each end, so longer lays are less wasteful than shorter ones. Without further ado, here is the order that the customer sent me to make the markers:.

quiz_cut_order_planning

Details needed to solve this challenge:

1. Yardage needed per size:

yardage_per_size

2. The maximum length of the contractor’s cutting table is 20 feet.

3. The contractor can spread no more than 30 layers of fabric.

4. The white and black fabrics are the same width so they can be cut together.

Your challenge is to analyze the variables to come up with the cut order plan so markers for this customer’s order can be cut and sewn -and at the lowest cost (fewest markers) possible.

Bonus points will be awarded for calculating the total yardage needed for each marker, by color.

——–

PS: If this is too much work (and I’m with you on that) or too confusing to solve, realize that this difficulty is a key reason that contractors don’t want small orders. We can only charge so much for making a marker but since small orders can be so much more complex than large ones, it is not unusual that cut order planning for small orders, takes (comparatively) much more time. For comparison, it might only take me an hour to develop the cut order plan for a large order but a small one, can take 2 or 3 times longer. The customer often thinks they’re being charged a penalty for being a small company, not realizing that the smaller order really is more work. The intended result of all of this, of course, is to understand how cut order planning works so you can place orders that are in keeping with your budget. At the very least, you will understand how you will need to compromise on your size order quantities if and when we present you with some suggested alternatives. The latter is the biggest hint I’m going to give you with respect to solving this problem. Well, that and pages 116-118 specifically, in the book.

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18 comments

  1. Penelope Else says:

    My head hurts! The main thing I remember is about pairing up sizes in some way, so you have a S + M + L to fit on the marker. But here the numbers of each size vary, so I’m wondering if it’s okay to pair them by items wanted, given that the yardages add up the same way?

    I can’t get further than that without the book!

  2. Kathleen says:

    Penelope: yes, the book will be helpful. Don’t forget that you can increase multiples by increasing the number of plies. In other words, if you draw the medium in once but have 10 plies, you have a total of 10 mediums. If you needed 10 of every size except 30 of the medium, you would draw in each size (except medium) once, and lay 10 plies. You’d have to draw in the medium 3 times to get 30 of those. To make sure this plan will work, you’d then have to add the yardage for each of those sizes plus Mx3, to see if this would fit the length of the cutting table. Does this explanation help anybody? Maybe I should back up a bit in the next post to explain this. Actually, it would be a duplicate of information in the book so maybe it should go into the forum.

    Considering the dearth of replies, I’m thinking that the follow up post should explain that it isn’t equitable for one to complain about the higher costs of processing small orders because it is several orders of magnitude more complex and time consuming to figure out than large orders. If one can’t calculate the plan themselves, one has to pay somebody else to figure it out.

    I’m wondering whether an online video seminar illustrating this would be helpful. I could not do it for free tho. Until one gets to the cut order plan, you really don’t know what your production order is going to cost -to include shorting orders for some customers vs potentially carrying dead stock.

  3. I just faced a similar spread and what I would do (and did) here is lay out S, M, L, XL together and lay the M and L twice (you also said this above). That gives you 30 M and L and 15 S and XL if you use 15 layers. I’d use a second marker for S and XXL on 3 layers. I don’t know if this would fit their table (I have 64 feet) and I’m far too tired from my own production issues to figure out their yardage!

    What I can say is that it’s a complicated issue and worth every penny you charge. It would be MUCH easier to just lay out even spreads on whatever fabric you have and cut away (which is what I’m moving towards).

  4. Judy Gross says:

    Marguerite, you don’t need to use a second marker – place the XS and XXL first on the marker,place a mark on the table (a piece of tape) where the XXL ends. Now, when you spread the fabric, spread 3 full marker lays of the white, (or black), then, start the next lay where your mark is on the table to cover the rest of the sizes you need. Then when you switch to the other color – again, 3 full lays of that color, and then the rest are shorter plys. I often have to do this when I need so many of a color in a particular size. To make life easier for me this way – it uses more fabric, but the customer pays for that – I will not mix sizes in the spread – so I have each size marked with a line separating them. This way, I can mix colors, and quantities of sizes. It takes a few minutes to plot it out, but this works for me.

  5. Quincunx says:

    Only three items of two of the sizes? I will make a separate figure for those. (3 x 0.8) + (3 x 1.3) = 6.3 yards of white and 6.3 of black for sizes XS and XXL. That is longer than the 5 yard table of the contractor. But 3 XSes and 2 XXLs are 5 yards exactly. One ply, one layer. They can be put aside on a different, very expensive because only one ply, cut if there is a need.

    That leaves 1 XXL (1.3) and all the S M L XL still to cut. First, the black fabric. 10 x (0.9 + 1.0 + 1.1 + 1.2) = 42 yards of black fabric and still no XXL. That has to take up seven plies on the table so add on .7 for the buffers on the ends. That is 42.7 yards of black fabric. And of white fabric also so we can get more use out of this marker. [I left out a thought here.] And there is too much waste in this marker so I am going to drop this in a reply and restart.

  6. Quincunx says:

    This time I am going to start with the table size and not the ratios. I am keeping the single ply of black and of white 3 XS + 2 XXL, for now.

    How many size L can I fit on the table at a time maximum? Four and not have enough room left over for a small. Three and 1.6 yards left over for one other cut of any size. Two and 2.8 left over for two other cuts of any size. The more Ls on the table at a time the less waste.

    [The waste would go down by a lot if the Small could be cut into 0.5 from one layer and 0.5 from the next. Without the pattern pieces though I cannot say that this is doable.]

    A layer of 3 Ls and 1 S is (3 x 1.1) + 0.9 = 4.2 yards and almost enough scrap for a S. Not good. Make a note that 3L + S + XS is an option but not for now. A layer of 3 Ls and an XL is (3 x 1.1) + 1.2 = 4.5 yards and .5 yard of waste.

    A layer of 3 Ms and 1 S is (3 x 1.0) + 0.9 = 3.9 yards and space enough for adding an L and NO waste! Save that one. Lay that marker out with ten plies of white and five of black. You will get five more black Ms than you ordered, so hey, “free” sales samples.

    You have two full length markers yet still need 1 XXL (1.3), all the XLs, 5 black Ls, 20 white Ls, 5 black Ss, 5 white Ss. Time to take care of all those 5s. A layer of 1 S and 1 L and the remainder filled in with XLs is 0.9 + 1.1 + (2 x 1.2) = 4.4 yards and 0.6 waste. The first waste that must be done. At least it is only five plies of white and five of black. [I want to split and re-lay that stack of waste and see if I can’t eke out garments from that half-length requirement, but does industry ever re-lay fabric that was laid out and cut? Or at least squeeze out that single missing XXL from those scraps.]

    You have three full length markers yet still need 1 XXL, 5 white XLs, 15 white Ls. The ratio is clear now. 3 L and an XL is (3 x 1.1) + 1.2 = 4.5 yards and .5 of waste, laid out on five plies of white.

    You have four full length markers:
    1 S : 3 M : 1 L, ten white plies, five black plies.
    1 S : 1 L : 2 XL, five white plies, five black plies.
    3 L : 1 XL, five white plies.
    3 XS : 2 XXL. . .either one ply white and one black, and be short one XXL,
    or two plies white and two black, and have too many XSes.
    And those five extra black size Ms, but those are a popular size.

    And from the timestamps, this took about an hour and a half to figure.

  7. Quincunx says:

    Oh wait. You do not HAVE to pull the fabric out to the full 5 yards every time, do you? That gets rid of the ‘waste’. So! Yardage! There is an extra .1 on every ply to make the “buffer”. So.

    10 white @5.1yards = 51 yards white
    5 black @5.1yards = 26.5 yards black
    5 white @4.5yards = 22.5 yards white
    5 black @4.5yards = 22.5 yards black
    5 white @4.6yards = 23 yards white
    and let’s just commit to having far too many XSes
    2 white @5.1yards = 10.2 yards white
    2 black @5.1yards = 10.2 yards black

    106.7 yards white fabric
    59.2 yards black fabric
    and costs for taking up the cutting table with FOUR different markers with a tiny little order. One of those markers was almost just one layer! Waste! Of! Time!

    Someone from the business will be along shortly to point out how to stop being so wasteful of the contractor’s time. I hope.

  8. sunday kind says:

    I admit I had to do an excel calculation to work this out… let me know if you care to see it!

    Marker no 1:
    1 each of sizes S, M, L, XL > marker length of 4.2 yds
    15 plies white, 10 plies black > 63 yds of white, 42 yds of black plus buffer lenghts

    Marker no 2:
    3 each of sizes XS and XXL > marker length of 6.3 yds
    1 ply white, 1 ply black > 6.3 yds each plus buffer length

    Marker no 3:
    3 each of sizes M and L > marker length of 6.3 yds
    5 plies white, no black > 31.5 yds of white plus buffer length

    Total yardage (with buffers) = 102 yds white, 49 yds black.
    Correct number of garments cut.

  9. Quincunx says:

    Eh. I have just told myself that there are only three feet in a yard and not four. So. The old markers still work but they are even less useful than the cutting table. If the new post is not up by the time I have time I will rerun the question.

  10. Kathleen Fasanella

    These are great responses everyone and very much appreciated.

    I’ve decided that my follow up post will illustrate each of the proposed solutions. I’m not certain yet if each solution should be its own post (leaning towards that) or to stick them all together (cognitive overload?). Altho no solution is 100% correct (not sure that is possible anyway), many aspects of the solutions are worth a discussion. There’s a lot to learn from.

  11. Judy, that’s interesting. I didn’t think about one marker because I had black & olive for one and black & royal blue for the other. I see how I could have at least laid the black out more efficiently (quickly). I do mix sizes in my markers because if I don’t then I waste fabric and I am the customer! Those 3X really eat up the width and I need to pair them with other sizes.

    Marguerite

  12. Quincunx says:

    Only three items of two of the sizes is still a strange small number. This time their marker fits all three of XS and of XXL on the table at the same time, (3 x 0.8) + (3 x 1.3) = 6.3 yards, one ply each of black and of white. Put that aside until last.

    You have one full length marker yet need all of S, M, L, XL. How many size L can I fit on the table at a time maximum? Six with no waste. But I do not have that many more Ls than other sizes. I can fit four Ls, one XL and one M with no waste. But I still do not have a need for four. [Four is not a (math) factor for the amounts we need to cut. But since factor is used in the business definition everywhere else on F-I, I will not use that word again.] I can fit three Ls, two Ms and an XL with (3 x 1.1) + (2 x 1) + 1.2 = 6.5 yards and 0.1 yard unused table space. With this I cut 10 plies of white and 5 plies of black. Again I have gone over by five black items, but this time they are size large. That is not as useful. Forget using this marker.

    Instead swap L and M. Cut a marker with 3 M, 2 L, 1 XL on a length of (3 x 1) + (2 x 1.1) + 1.2 = 6.4 yard marker. 10 plies of white and 5 plies of black fabric makes five black Ms too many.

    This was easier when I thought the table length was a multiple of M. Not of L. I wonder why. We need just as many Ls as we do Ms.

    You have two full length markers yet need all of S, 10 white L, 5 white XL, 5 black XL. The number of layers in this marker is easy to see and to start with. 2 S and 1 XL is needed. But that is only (2 x 0.9) + 1.2 = 3 yards! Yes you can lay that out twice on a ply on this table but we only need five plies. Going to three plies and laying the marker twice will give you extra Ss and XLs! But not too many so I guess we can live with it. Or wait, we can lay that last ply only out to the 3 yard mark! The problem is solved. This marker will be 2 S, 1 XL, 2 S, 1 XL _in that order_ and with a buffer in the middle. (2 x 0.9) + 1.2 + 0.1 + (2 x 0.9) + 1.2 = 6.1 yards and three (2 1/2 really) plies of white and three (2 1/2 really) plies of black.

    You have three full length markers yet need 5 white S, 10 white L. We can reuse the trick of the last marker and use half the marker for the last ply. This marker will be 2 L, 1 S, buffer, 2 L, 1 S at (2 x 1.1) + 0.9 + 0.1 + (2 x 1.1) + 0.9 = 6.3 yards laid out on three (2 1/2 really) plies of white.

    You have four full length markers:
    3 M : 2 L : 1 XL, 10 plies white, 5 plies black.
    2 S : 1 XL : 2 S : 1 XL, 2.5 plies white, 2.5 plies black.
    2 L : 1 S : 2 L : 1 S, 2.5 plies white.
    3 XS : 3 XXL, 1 ply white, 1 ply black.

    And five extra black size M products. Or wait. Now that we know that trick of laying less fabric than the full length of the marker, we can choose not to lay out and cut those last black Ms. Make that an exact count instead.

    First marker yardage:
    10 white @ 6.5 yards = 65 yards white
    5 black @ 5.5 yards = 27.5 yards black

    Second marker yardage:
    2.5 white @ 6.2 yards = 15.5 yards white
    2.5 black @ 6.2 yards = 15.5 yards black

    Third marker yardage:
    2.5 white @ 6.4 yards = 16 yards white

    Fourth marker yardage:
    1 white @ 6.4 yards = 6.4 yards white
    1 black @ 6.4 yards = 6.4 yards black

    Totals: 102.9 yards white, 49.4 yards black.
    Note that I added .1 on markers that were not laid on a full ply and I am not sure that was necessary.

  13. Sreehari Chandra says:

    Marker 1: 3XS, 3XXL (Marker length: 3×0.8 + 3×1.3 = 6.3)
    Piles: White -> 1, Black -> 1
    White Yardage + Buffer = 6.3 + 0.11 = 6.41
    Black Yardage + Buffer = 6.3 + 0.11 = 6.41

    Marker 2: 1S, 2M, 2L, 1XL (Marker Length: 0.9 + 2×1 + 2×1.1 + 1.2 = 6.3)
    Piles: White -> 15, Black -> 5
    White Yardage + Buffer = 94.5 + 1.67 = 96.17
    Black Yardage + Buffer = 31.5 + 0.56 = 32.06

    Marker 3: 3S, 3XL (Marker Length: 3×0.9 + 3×1.2 = 6.3)
    Piles: Black -> 2
    Black Yardage + Buffer = 12.6 + 0.22 = 12.82

    Total Yardage for White (including buffer) = 6.41 + 96.17 = 102.58
    Total Yardage for Black (including buffer) = 6.41 + 32.06 + 12.82 = 51.29

    It produces 11S and 11XL for Black instead of 10S and 10XL.
    Remaining quantities are as per the order

    The last solution proposed by Quincunx (Laying less fabric for black, instead of full length for all piles)
    is very intuitive and interesting, however I am not sure if that is a common practice in the industry.
    Kathleen can you shed some light on this?

  14. Robyn says:

    Most pay for markers by # of sizes in marker. So the least amount of sizes to mark is better on the cost. I came up with 2 scenarios, one with 10 sizes in markers (4 markers) and one with 8 sizes in markers (3 markers) but neither would fit all on the length of the table. both scenarios came up with a spread of the black and white together, then another spread of white by itself.

  15. Mark says:

    I have absolutely no experience whatsoever of working this sort of thing out for either theoretical or practical purposes, but since maths can be fun I thought I’d give it a bash. What I came up with may be controversial, and it very probably wouldn’t work for practical reasons, but here it is anyway:

    Marker 1 (3 plies white; 3 plies black):

    3 XS (white) : 3 XXL (white)
    3 XS (black) : 3 XXL (black)

    Marker length = 0.8+1.3+0.17 (buffer) = 2.27yds (so it fits on the table)

    Yardage = 2.27*3 plies = 6.81yds per colour

    Marker 2 (15 plies white; 5 plies black):

    15 M (white) : 15 M (white) : 15 L (white) : 15 L (white) : 15 S (white) : 15 XL (white)
    5 M (black) : 5 M (black) : 5 L (black) : 5 L (black)

    Here you would need to lay different lengths of black/white fabric, and I don’t know if that’s the done thing!

    Total marker length = 1+1+1.1+1.1+0.9+1.2+0.39 (buffer) = 6.69yds

    This would be longer than the table, but it could potentially work if you reduce the size of each buffer area from 2″ to 1.88″ (hence controversy).

    New marker length = 1+1+1.1+1.1+0.9+1.2+0.37 (new buffer) = 6.67yds (yay, now it fits, with literally no room left to spare)

    Yardage (black) = 1+1+1.1+1.1=4.2
    1.88*5 = 9.4 (buffer in inches) = 0.261111yds
    4.2+0.261111 = 4.461111yds
    4.461111*5 plies = 22.31yds

    Yardage (white) = 1+1+1.1+1.1+0.9+1.2 = 6.3
    1.88*7 = 13.16 (buffer in inches) = 0.366yds
    6.3+0.366 = 6.67yds
    6.67*15 plies = 99.98yds

    Total yardage (white) = 6.81+99.98 = 107yds
    Total yardage (black) = 6.81+22.31 = 30yds

    I may have made one (or several) very basic mathematical error(s) in doing this. (I’m mean to be working!)

    If you absolutely can’t have a buffer that’s less than 2″ then the best I came up with was to have 3 markers, but I don’t have time to write that up now. Please feel free to tell me that I’m WAY off the mark!

  16. I’ve held off on commenting for a while, but this thought is nagging at me. And I don’t buy ready to wear because it’s not available in my size or it’s already sold out. So,I’ve stopped looking for it and started sewing for myself.

    Why only 3 in XXL. So many of us larger women would buy if we knew designers were designing for us. There’s a serious shortage of good looking clothing for those of us that either live on the edge of the size chart and on the other side of it (both small and large).

    On a business related note, why wouldn’t you choose the quantities per size based on your target market? If your target market is smaller, focus smaller. If your clothing appeals to a larger market, shift larger. If you take a little time upfront to gather a clear understanding of sizes of both potential customers and existing, likely you’ll sell more and have happy customers. Those aren’t the only factors, but any business spends time studying their target market first, otherwise their product misses the mark.

    For example, if you sell to professional women in seattle, you might run a few polls, starting with friends, to find out what their size is, what clothes they buy, and what areas of the body have fitting issues. You might discover they have the most money to spend on your product, are pear and apple shaped, but love a great fitting empire dress / shirt.

    This standard bell curve persists in the lack of good quality clothing for an increasing physical size of the population. Only a few people get the benefit of some amazing designs. And if we don’t want our designs to become fast & cheap fashion, the up front research would reduce waste and create a higher value.

    I hardly have all the answers, just voicing my thoughts and seeking to begin a conversation around this for deeper understanding. I do appreciate all the deep information around how much fabric is needed by size, then considering cutting table sizes, etc. Most intriguing. Thank you for taking the time to share. I know how much work it is to explain and diagram clearly for understanding.

  17. Quincunx says:

    *looks a long while at Mark rounding down the buffer amount where the general rule is ‘always round up for fabric usage’, but cannot see anything wrong with it*

    I know, I know, part 2 of this question was meant to show us that small orders sometimes have to choose ease of cutting over efficiency of fabric usage. But separate from that, maybe he is right and .1 yard can give two strips of buffer. It does not change much on this short table. It might effect a longer marker.

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