Clarke Joe, Lynch Colleen C. M&R Professional Screen Printing Series

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PAGE

. 11

ter covers inks and by using the floodbar to pamper and coerce the inks, the

flood will indirectly boost productivity.

DDoouubbllee IInnddeexx

There is a great deal of confusion surrounding the option to double index. It is

an exceptional feature standard on all Gauntlet and Challenger presses but

intended for a niche of production. Before you plan to do wondrous things to

your productivity, first consider who the double index feature is intended for;

1. Presses with high color capacity.

2. Presses with 2 load and 2 unload stations.

3. Extremely long runs.

4. Extremely well engineered printing conditions.

5. Minimum two extra persons on press.

6. A dryer / press configuration that permits double load and

unload.

7. Two jobs that fit on press at the same time and the same run

length. Example: a two-sided job.

We will offer a two-sided job of four colors per side and no flashing as an exam-

ple of double index. The press is a twelve color with ten heads. The last two

heads have been removed to accommodate a second load and unload station, and

it is to be set up as follows. We are going to run only five shirts of each design or

each side of the tee shirt.

In normal operation one garment is loaded and the press indexes, raises and the

heads print and the indexer lowers and is ready to index again. With double

index, the press indexes, lifts, lowers indexes, lifts and then the heads print. The

indexer lowers and prepares to index again.

The advantage is that with two more persons on press, you can be producing two

sides at a rate that is typically 30% faster than running one side and then a second

side. If the job is simple and very long, it may be worth the effort. The actual

speed will depend on your squeegee speeds; lift cylinder timing and dwell times as

well as the air volume and pressure supplied to the press.

Costing

PAGE

. 12

RMC (Raw Material Cost) Control

It will behoove you to control your raw material coststhe point is to control

them wisely. If your best price is on a low solids emulsion, a mesh with imbal-

anced stress strain curves, an ink that builds up or an ill-engineered blade you

may be getting the best price but you are doing your company a disservice.

LLiinnee IItteemmss OOnn TThhee GGeenneerraall LLeeddggeerr

You or your purchasing agent know that if you cut costs by a dollar, it goes

directly to the bottom line and it therefore becomes profit, virtually all of it.

Before you push too far in this singular direction you may want to review the

contents of this manual. It makes recommendations not on the cost of the raw

material or supply item but on the value of that product to your goals of higher

productivity and better quality. Some comprehension of what these products do

is needed to help you make the best decision as to the value of the product. We

are not recommending that you arbitrarily pay more but that you consider the

ramifications of your decision on productivity and quality.

Chapter 6

Double Index Mode

Index 1

Index 2

Index 3

Index 4

Index 5

Index 6

Index 7

Index 8

Index 9

Index 10

Index 11

Index 12

Figure 6.7 The table above shows one complete cycle of two images run simultaneously as a double index order. L

means load, P stands for print and U means unload. The first job is A and the second is B they are each five color

images (a front and back as an example) and running on a twelve color Challenger press. Index is noted on the left hand col-

umn and marks the times that the press indexes. The field of data shows the stage of production. At index number twelve,

you would have five completed shirts (on both sides) and could begin to reload two more shirts, one front and one back.

PAGE

. 13

WWhheetthheerr TToo AAdddd AA SSccrreeeenn OOrr NNoott

There is a real world issue that plagues those who print short run darks

whether to run one or two white screens. The debate has been around a while

because the answer is not intuitive but let us explain. There are four possibilities

to get a better white (when one hit isnt enough) with screens, strokes and flash:

1. Print, flash, print and flash.

2. Second screen, one flash.

3. Double Stroke.

4. Revolver Mode.

The first one will use two white screens and give you exceptional results at top

production speeds for any run length. Number two will give you better than one

hit results at top speed but not as good as the first option. Number three will

improve the white but will cost you a nominal third of your productivity (see

page 6.5). The fourth option is an M&R exclusive but is not designed to be the

best solution here. The Revolver will run at a fraction of the standard Gauntlet

or Challenger speed.

So how do I know when to use a second screenthe answer is simple but based

on several variables:

1. Time it takes to set up the second screen.

2. Standard production rate in dozen per hour.

3. Increase in productivity with second screen.

4. Profit per print in dollars.

5. Screen cost in dollars.

The decision is to be based primarily on a twofold question; how long did you

delay the press to set up the additional screen and how long will it take you to

make up for that downtime at the improved rate? The profit and the cost of the

screen are truly secondary to the decision.

To make the reality obvious to all, lets take a very conservative scenario. We have

used a cycle rate on a Gauntlet (or Challenger) of 45 dozen per hour. We suggest

the increase in productivity is only 10% over double stroking. We allow 5 minutes

to set up and changeover the second screen.

Costing

PAGE

. 14

So in our scenario you would want to use a second screen for any and all orders

over 523 pieces. The series of five graphs below detail how each of the variables

impacts the decision to run a double stroke or worse or to use a second screen.

Of course the entire profile is predicated on the basis that you do want a better

white. You may choose to run a single stroke and ship the product, the choice is

yours but if you are not satisfied, we want to help you make a measured decision.

M&R has designed and engineered features specifically

to let you reduce your downtimeset-up is a key factor

in the downtime equation. Leading the list is the Tri-

Loc registration system. The screens can be simply and quickly loaded from the

front of the press with no tight fits. Standard on the presses are pneumatic screen

locks as well as pneumatic squeegee and flood bar locks. No tools are needed for

changing or adjusting the position of the platens. Likewise you will not need

tools for setting the off-contact distance or adjusting the angle of either blade.

Chapter 6

Variable

Example 1

Cycle Rate (dz./hr.)

Percentage Increase

10%

Set Up / Changeover (mins.)

Cost Per Screen

$7.00

Gross Profit

25¢

Breakeven Production Only

495

Breakeven Screen Cost Only

Breakeven Total

523

Figure 6.8 This table shows Example

1 data used in the next five graphs to

exemplify the impact of each of the vari-

ables on the decision to double stroke or to

shoot a second white screen. The scenario

indicates that under 523 pieces, a second

white screen would be questionable. This is

due to a low percentage increase (10%)

with the second screen. Refer to page 6.17

for Example 2.

Figure 6.9 This chart graphs the

insignificant cost of reprocessing a

screen and its impact on the decision

whether or not you should shoot an

extra screen to get better looking

white ink images. The nominal cost

of reprocessing a screen is estimated

to be between $4.00 and $7.00.

This includes, wash-up, reclamation,

degreasing, coating, exposure, devel-

opment and touch-up. It amortizes

typical costs of mesh and frames.

The fairly wide swing from four to

seven dollars is due primarily to

coating costs, the screen mesh and

type of frame. As the graph shows,

the cost of the screen has little

impact on the minimum run length

where you should shoot a second

screen.

Variable: Screen Cost

100

200

300

400

500

600

700

800

900

1,000

$4 $5 $6 $7 $8 $9 $10

Dollars Per Screen

Min. Run Length

To Justify 2nd White Screen

The presses include front and rear micro register to let

you fine tune even if the frame is not agreeable. Once

you are ready to proof a print, simply flip the switch to

test mode and one garment only will index and print

only at the proper times.

If you consider a high screen cost and low profit, $7.00

and 10¢ each but use a Tri-Loc to register and set up in

3 minutes, run at 45 dozen per hour since the run

lengths are small and expect an increase of 35% over a

double stroke, the break even number of pieces is 174.

So anything over 174 pieces warrants a second screen.

Figure 6.11 This chart plots the

cycle rate against the break even

run length for determining whether

or not to use a second screen or to

double stroke. If it appears to you

that the faster you go, the worse it

gets it is true but the reason is sim-

ple. The bulk of the cost is related

to the time it takes to set up a

screen. The value of that time is

the cycle rate that could be in place

if we werent setting up that screen.

There are a few considerations how-

ever. First we are talking about

short runs where the cycle rate is far

less important than the downtime.

It is unlikely that you will run at

or near top press speed (refer to fig-

ure 7.37 for details). Second if you

are double stroking, you just cant

run very fast as you may discover

when you look at figure 7.2. Third

as you increase in speed the value of

time improves. Still the overall

impact can be significant.

PAGE

. 15

Costing

Variable: Gross Margin

100

200

300

400

500

600

700

800

900

1,000

$0.10 $0.20 $0.30 $0.40 $0.50 $0.60 $0.70

Margin Per Print

Min. Run Length

To Justify 2nd White Screen

Figure 6.10 This may dispute

the normal business sense because it

shows that the gross margin per

print has little to do with minimum

run length. Therefore it has little to

do with the decision to double stroke

the white or to shoot a second screen.

The range of profit is from 10¢ to a

high of 70¢ and yet the commensu-

rate change in the break even run

length is minimal. It improves

slightly as the profit approaches

zero. So the profit is not the answer

to our question.

Variable: Cycle Rate

100

200

300

400

500

600

700

800

900

1000

25 35 45 55 65 75 85

Dozen Per Hour

Min Run Length

To Justify 2nd White Screen

PAGE

. 16

Chapter 6

Figure 6.12 This chart cuts to

the core of the matter as it plots

cycle rate in dozens per hour against

the break even run length. If you

anticipate a 10% increase in produc-

tivity with a second white screen your

minimum is over 500 pieces.

Conversely if you anticipate a 40%

increase with a second screen, you

will find that your minimums are

below 200 pieces (in example num-

ber one). This is one of two facets

that will have a very serious impact

on your decision.

Figure 6.13 This photo-

graph shows the results of

an extra white screen and

all single strokes printed on

a Challenger press. One

white screen would not give

the coverage or surface need-

ed. A double stroke would

have cut productivity. The

second screen was added and

the job ran at over 750

pieces per hour. This HiRes

AccuColor

garment com-

pliments of Target Graphics

Ltd..

Variable: Percentage Cycle Rate

100

200

300

400

500

600

700

800

900

1000

10% 15% 20% 25% 30% 35% 40%

Percent Increase In Cycle Rate

Min. Run Length

To Justify 2nd White Screen

RReeccaappppiinngg

RRaaww MMaatteerriiaallss

Sometimes there is a gap between those with the authority and those actually

doing the work. What the most successful shops have in common is that they

have eliminated (or at least reduced) that gap. To know which of your materials

has a greater value you will have to test and record the data. Please only change

one variable at a time and dont assume that if I swap one mesh for another that

it will fit ideologically into the slot that I have provided. If you want to test fairly

you will have to tailor your recipe to accommodate the new ingredient. If you are

curtailing costs, it may be the best thing that you can do. If you to zealous in the

job of cost cutting then it may come back to haunt you when you go to press.

Break-Even Operation

Our hypothetical company has one automatic press, runs at 75% of annual

capacity for eight hours a day, five days a week. Its monthly overhead is $34,600.

We have varied the set up times and cycle rates independently to show the effect

Figure 6.14 This is the final

plot and has by far the greatest

affect on the decision whether to dou-

ble stroke or to use a second white

screen. If you can set up in two

minutes (of course you would need a

Tri-Loc, well engineered art and

screens, a calibrated press and a

trained staff) your minimum run

length would be just over 200 pieces.

If at the other extreme it takes you

eight minutes to set up your mini-

mum run length at a 10% increase

in percentage of cycle rate is over

800 pieces.

PAGE

. 17

Costing

Variable

Example 2

Cycle Rate (dz./hr.)

Percentage Increase

35%

Set Up / Changeover (min.)

Cost Per Screen

$7.00

Gross Profit

25¢

Breakeven Production Only

104

Breakeven Screen Cost Only

Breakeven Total

132

Figure 6.15 Example 2 similar to

Example 1 (figure7.8) with only two ele-

ments changed; the percent increase was 10

percent and is now a far more realistic 35

percent. You may want to refer to page ___

for details on the cost of a double stroke.

Also the set up time went from 5 minutes

to an impressive 3 minutes. With these two

changes, the minimum run length is 132

pieces.

Variable: Set Up Time

100

200

300

400

500

600

700

800

900

1000

2345678

Set Up and Changeover Minutes

Min. Run L:ength

To Justify 2nd White Screen

PAGE

. 18

that these changes have on

both the minimum run length

and the break even price.

Minimum run length identi-

fies the quantity of tees that

you need to print to break

even. The percentage of

capacity is the amount of the

year that you are operating at

average rates versus the time

that you are operating at less

than average. Simply put, if

you operate at 100% for the

first two quarters of the year

and at 25% during the slow

season, your percentage of

plant capacity is 75%.

Break even operation is that

point between profit and loss.

If you make a profit buy cut-

ting costs, increasing the price

or both, then you are prof-

itable, no longer at break even. If you are at break even and lose due to higher

costs, lower pricing or both then you suffer a loss. The only to be extremely pre-

Chapter 6

To increase the speed at which you can make

changeovers follow these steps:

1. The last job comes to an end.

2. Loader removes the squeegee and

floodbar from head number one.

3. Loader removes screen from head

number one.

4. Put screen aside until later.

5. Loader goes to head number two

and repeats.

6. Unloader begins to set up head

one.

7. Have backup blades ready.

8. Since setup has begun, changeover

has ended.

9. Changeover takes two minutes

regardless of the complexity of

the job.

Making Faster Changeovers

How To

Instructions

Variables

Units

Run Length

Pieces

Breakeven Point

Dollars

Monthly Overhead Total

$34,600

Hours Per Month Worked

173 (5 days-per-week of eight-hours)

Set Up (includes changeover)

Minutes

Minimum Run Length

Pieces

Cycle Rate (in dozen-per-hour)

Dozen Per Hour

Percent Plant Capacity (annualized)

75%

Figure 6.16 This table lists the variables used to compute our break even point on the left side and their units on the

right. Our hypothetical shop has an overhead of $34,600 per month and works straight time. The year-end plant capacity

is 75%. All other variables are used as such and solved for in the tables below.

PAGE

. 19

cise and accurate in your cost estimate your costs are to gather a lot of actual

data on set-up and changeover times cycle rates and productivity. Amass a history

of ink consumption, per mesh and design. Consider the impact of capacity and

labor utilization as well as seasonal trends. To evaluate the cash position and cost

of money as factors in your costing. With this effort, you can be reasonably cer-

tain of your costs. What we offer here is a short and sweet estimate of the break

even costs and minimum run lengths of a hypothetical company.

SShhoorrtt RRuunn LLeennggtthhss

The run lengths listed here are 288 pieces and under. The lesson is to compare

the effects on the break even as well as the minimum run length as the set-up

time and the cycle rate of production are varied. You will clearly see that the

effect of the set-up is most critical. Later we will cover the same lesson with 3600

pieces run lengths. The needs of short and long run lengths differ greatly. How

great is just the point of this exercise.

Costing

Breakeven Point

$1.75

$1.52

$1.29

$1.06

$0.83

$0.60

$0.48

Monthly Overhead

$36,400

Hours per Month

173

Set Up Time

7.5

Min. Run Length

288

Cycle Rate (dz/hr)

Percent Plant Cap.

75%

Figure 6.17 This table lists short run costs as affected by set-up time. The darker gray areas mark the chaining variables

in the series of tables. The lighter gray areas mark the variable areas compared here and in the graph below. You can see the

cost drops dramatically as the set-up time is reduced. For example if your set-up time is 45 minutes and drops to fifteen

minutes, the break even plummets from $1.29 to $0.60 each. This is over a 50% reduction in the break even point.

Reduction in setup time is one way to improve your ability to bid on the short runs.

Variable Set Up Time

To Achieve Breakeven

$0.40

$0.90

$1.40

$1.90

$2.40

90 75 60 45 30 15 7.5

Set Up / Changeover In Minutes

Breakeven Point

Figure 6.18 This chart illus-

trates what happens to the break

even point (that position between

profit and loss) with a change in

setup time. In our scenario the

break even plummets as the setup

time decreases. The range is a high

of $1.75 to a low of $0.48 and it

is controlled by the setup time. Refer

to page 6.18, figure 6.16 for the list

of variables which apply to this

profile.

PAGE

. 20

Chapter 6

Breakeven Point

$1.43

$1.25

$1.13

$1.06

$1.01

$0.97

$0.94

Monthly Overhead

$36,400

Hours Per Month

173

Set Up Time (min.)

Min. Run Length

288

Cycle Rate (dz./hr.)

Percent Plant Cap.

75%

Figure 6.19 This table illustrates short run costs as affected by press cycle rate. Although the cost drops and it is appre-

ciable, it is not nearly as impressive as the cost savings from a reduced set-up time. For example if your cycle rate is 50

dozen per hour and you improve to 60 dozen per hour the savings goes from $1.13 to $1.06. Reduction in setup time, not

an increase in cycle rate is the best way to cut costs on the short runs.

Variable Cycle Rate

To Achieve Break Even

$0.40

$0.90

$1.40

$1.90

$2.40

30 40 50 60 70 80 90

Cycle Rate In Dozen Per Hour

Breakeven Point

Figure 6.20 Because the graph profiles a short run order, the cycle rate has little

affect on the break even point. Of course the point will descend as the cycle rate

increases but the descent is very gradual. For short runs the key to minimizing the

break even point is not the cycle rate. Refer to page 6.18 for the list of variables,

which apply to this profile.

Breakeven Point

$1.75

Monthly Overhead

$36,400

Hours Per Month

173

Set Up Time (min.)

7.5

Min. Run Length

288

240

192

144

Cycle Rate (dz./hr)

Percent Plant Cap.

75%

Figure 6.21 This table lists the minimum run length as affected by set-up time. The break even point is frozen at $1.75

per print. You can see the minimum run length drops dramatically as the set-up time is reduced. For example if your set-up

time is 45 minutes and drops to fifteen minutes, the minimum run length plummets from 144 to 48 pieces. This is a 67%

reduction in the run length. Reduction in setup time is one way to improve your ability to print shorter runs at a fixed break

even.

Clarke Joe, Lynch Colleen C. M&amp;R Professional Screen Printing Series

Подождите немного. Документ загружается.

Clarke Joe, Lynch Colleen C. M&R Professional Screen Printing Series