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

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PAGE

. 21

Costing

Variable Set Up Time

To Achieve Minimum Run Length

100

150

200

250

300

90 75 60 45 30 15 7.5

Set Up / Changeover In Minutes

Min. Run Length

Figure 6.22 With a fixed

break even point of $1.75 per

print, the setup time has a major

impact on the minimum run length

to achieve that break even. A fif-

teen-minute setup would allow you

to meet the break even in forty-eight

pieces. Refer to page6.18 for the list

of variables, which apply to this

profile.

Breakeven Point

$0.97

Monthly Overhead

$36,400

Hours Per Month

173

Set Up Time (min.)

Min. Run Length

288

196

152

144

138

135

132

Cycle Rate (dz./hr.)

Percent Plant Cap.

75%

Figure 6.23 Listed are the minimum run length as affected by press cycle rate. The break even point is frozen at $0.97

per print. You can see the minimum run length drops gradually as the cycle rate increases. For example if your cycle rate is

50 dozen per hour and you improve to 60 dozen per hour, the minimum run length only drops from 152 to 144 pieces.

Reduction in setup time, not and increase in cycle rate is the best way to reduce the minimums with a fixed break even.

Variable Cycle Rate

To Achieve Minimum Run Length

100

150

200

250

300

30 40 50 60 70 80 90

Cycle Rate In Dozens Per Hour

Min. Run Length

Figure 7.24 At a $0.97 break

even point the cycle rate haws a sig-

nificant impact only if you are run-

ning very slowly, under fifty-dozen

per hour. After that the increase is

not significant when compared to

changes in the setup time. Refer to

page 6.18 for the list of variables,

which apply to this profile.

PAGE

. 22

SSeett-UUpp TTiimm

M&R engineering has taken a long hard look at the reduction

of downtime and responded with a wide range of standard

features, accessories and attachments. Features such as The

Tri-Loc registration system, (see page 4.48) enables you to

drop your minimums and keep the press running even on the

shortest orders. Pneumatic screen clamps, squeegee and flood-

bar clamps, make setup a simple matter of flipping a switch.

The Challenger II comes standard with pressure control on

the squeegees. Rear Micro Register is available for those tough

or twisted jobs that refuse to cooperate (see figure 6.18). Set-

up and changeover is critical for all work but most important

in short run lengths. Following is a list of steps to be taken to

insure the best use of the press and to minimize set-up time:

1. Always have a readied set of screens for the next

job, just in case. Make them twenty-four hours ahead

of time, they wont cost you more and it wont take

more effort, only a decision to do so.

2. Keep your press in calibration (page 4.15). Press cali-

bration is the heart of the system, the foundation

upon which you will build your quality and produc-

tivity, dont shortchange it.

3. Have clean squeegees and floodbars ready at the

press. Never hold your press from running while you

clean up anything, it is too valuable. One back up on

floodbars may be sufficient but if you follow our

prescription, you will use two durometer blades so

two back up sets is the best investment.

4. Make color matches the day prior to the run. For no

more effort, and a bit of planning you should never

have your press waiting for a color or color match.

5. Strike off all color matches for prior approval. Use

your Chameleon or other manual press to pretest the

color before going to press. The potential for a man-

ual to compete against an automatic is near zero. Use

your manual effectively to free time on the automatic.

M&R has loaded features on the

Gauntlet and Challenger presses

so that you can run at top produc-

tion speeds. The Mosier air cylin-

der that is at the heart of the

press has been time tested for

excellent performance. Its opera-

tional speeds justify the use of

automatic loading and unloading.

The shirt detector is the perfect

training aid and even with a sea-

soned veteran, it can help raise the

level of productivity without any

increase in rejection. The detector

senses when you miss a platen and

dont get a shirt loaded in time.

That platen is automatically

skipped through the cycle and the

operator doesnt have to respond

or stop the press.

Independent squeegee and flood

bar speeds allow you to maximize

the productivity and still pamper

the ink. Front and rear stroke

lengths adjust (available on the

Challenger series presses) allow

you to shorten the stroke to fit

the job. As this chapter illustrates,

the stroke and speed of the blade

can help or hurt production.Air

regulators and gauges for

squeegee pressure control are

available as an option on all M&R

presses. This allows you to tailor

the pressure to the job. It resolves

the problem of premature screen

breakdown by allowing you to

only use the force needed.

Chapter 6

M&R F

eatures

or T

oduction Speeds

PAGE

. 23

6. Have all paperwork at press side the morning of the

run. This is a clerical function and should never keep

the press waiting.

7. This is not the time to clean up the press. Do all of

your maintenance and cleaning before or after regu-

lar production hours.

8. This is not the time to changeover the press.

Changeover should take no more than two minutes,

regardless of the complexity or length of the job.

(Clue: the press can only be in one mode at a time;

idle, setup, production or changeover.)

9. Keep and file time logs of all press activity. Without

time logs you have no real way to gauge your per-

formance. Improvements wont be appreciated and

counter productive activity will be tolerated.

10. Standardize stroke, flashes, blades, off contact and

placement. Unless the step adds value to the print-

ed garment, try your best to eliminate it from your

regimen. By setting the press at a home calibra-

tion point, you can alter as needed, but always can

return home.

11. Make all bodies available to expedite set-up. If the

press is your sole source of revenue, then there is

nothing that is more important than making sure

that it is operating at its maximum efficiency. There

are times when you will want to throw labor at the

problem.

CChhaannggeeoovveerr

Changeover more lovingly called tear-down should never

take more than two minutes even if the job is a fourteen color!

Have one person go to the first color head and remove the

screen, the floodbar and the squeegee. Get them out of the

way so that the next person can immediately begin set-up.

Now the changeover and set-up run concurrently. As soon as

one is done with changeover, he should help complete set-up.

With quick-release, no-tools platens there is nothing that will

Quartz flash units feature no

warm up and accommodate the

highest production in the industry.

Peel adjust (available on

theUltimate and Formula presses

only) is a feature that can save a

job on press. It can allow you to

compensate for a wide range of

inequities with the turn of a knob.

Finally our low profile platens

permit high-speed loading with a

minimum of operator fatigue.

M&R presses are not just for the

best quality printing but for the

top productivity as well.

Costing

M&R F

eatures

(Continued)

PAGE

. 24

stand in your way of getting back into production. The point is not to delay the

start of the set-up mode.

LLoonngg RRuunn LLeennggtthhss

As the run length increases, set-up time becomes less and less critical and cycle

rate more and more critical. The tables below begin at 300 dozen (3600 pieces)

and show the impact of both facets of the press run.

Chapter 6

Breakeven Point

$0.48

$0.44

$0.42

$0.40

$0.38

$0.37

Monthly Overhead

$36,400

Hours Per Month

173

Set Up Time (min.)

7.5

Min. Run Length

3600

Cycle Rate (dz./hr.)

Prct. Annual Plant Capacity

75%

Figure 6.25 This table lists long run costs as affected by set-up time. You can see the cost drops slowly 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 only drops from

$0.42 to $0.38 each. An increase in cycle rate (below) as opposed to a reduction in setup time is one way to improve your

ability to bid on the short runs.

Variable Set Up Time

To Achieve Break Even

$0.30

$0.40

$0.50

$0.60

$0.70

$0.80

90 75 60 45 30 15 7.5

Set Up / Changeover In Minutes

Break Even

Figure 6.26 At a 3600 piece

run length and a sixty second cycle

rate, setup has very little impact on

the break even point for our sce-

nario. You will find that the same

conditions respond rapidly to a

change in cycle rate. (Refer to page

___ for the list of variables, which

apply to this profile).

Breakeven Point

$0.79

$0.61

$0.50

$0.42

$0.37

$0.33

$0.30

Monthly Overhead

$36,400

Hours Per Month

173

Set Up Time (min.)

Min. Run Length

3600

Cycle Rate (dz./hr.)

Prct. Annual Plant Capacity

75%

PAGE

. 25

Costing

Figure 6.27 The table, on the bottom of the previous page, lists the long run costs as affected by press cycle rate. The cost

drops dramatically and the break even is fixed at a lower rate due to the length of the press run at 3600 pieces. For exam-

ple if your cycle rate is 50 dozen per hour and you improve to 60 dozen per hour the savings goes from $0.50 to $0.42 a

savings of 16 percent. On a long run a sixteen percent saving is appreciable. An increase in cycle rate, not a reduction in

setup time, is the best way to cut costs on the long press runs.

Variable Cycle Rate

To Achieve Break Even

$0.30

$0.40

$0.50

$0.60

$0.70

$0.80

30 40 50 60 70 80 90

Cycle Rate In Dozen Per Hour

Break Even

Figure 6.28 This chart takes a

relatively long run of 3600 pieces

and fixes setup at 45 minutes and

then compares an increase in cycle

rate to the break even point. At 30

dozen you need $0.80 to break even

but move up to 50 dozen per hour

and $0.50 will be the point right

before profit. Refer to page 6.18 for

the list of variables, which apply to

this profile.

Breakeven Point

$0.79

Monthly Overhead

$36,400

Hours Per Month

173

Set Up Time (min.)

7.5

Min. Run Length

4656

3880

3104

2328

1552

776

388

Cycle Rate (dz./hr)

Percent Plant Cap.

75%

6.29 This table lists the minimum run length as affected by set-up time. The break even point is frozen at $0.79 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 2328 to 776 pieces. This is a 67%

reduction in the minimum run length. Reduction in setup time in addition to faster cycle rates is one way to improve your

ability to print long runs at a fixed break even.

Variable Set Up Time

To Achieve Minimum Run Length

1,000

2,000

3,000

4,000

5,000

90 75 60 45 30 15 7.5

Set Up / Changeover In Minutes

Min. Run Length

Figure Figure 6.30 This chart illus-

trates a fixed break even point of $0.79

and a fixed cycle rate of sixty dozen per

hour. In this scenario the setup and

changeover time has an overwhelming impact

on the minimum run length to break even.

Refer to page 6.18 for the list of variables,

which apply to this profile).

PAGE

. 26

TTrraaiinniinngg PPrreessss LLooaaddeerrss

There is a level of press operator that can be very beneficial in your shopthe

high-speed loader. This person can be trained on an M&R press in hours and

load at fifty to seventy dozen per hour. They will not be the top troubleshooter,

nor will they be the best at setup but they will be able to load a press at top

speeds.

There are a number of advantages; first it is a very trainable position. Second it

can give your top performers a break. Third it is an excellent step toward cross

training. Here is a map for how to optimize training. First familiarize the novice

with the controls, including emergency stop and the most frequently used fea-

tures during press operation.

Have the person who is your top loader do the training and stay with the novice

while he or she is learning to load. If possible move a head out so that you will

have two load stations and put new and old operators at each position. (Consult

M&R service before you attempt to do this for the first time.) Now the novice

has a safety, it is the veteran. If there is a problem, little can go wrong.

Chapter 6

Breakeven Point

$0.79

Monthly Overhead

$36,400

Hours Per Month

173

Set Up Time (min.)

Min. Run Length

2962

1023

652

525

461

422

396

Cycle Rate (dz./hr.)

Prct. Plant Capacity

75%

Figure 6.31 This table lists the minimum run length as affected by the press cycle rate. The break even point is frozen at

$0.79 per print. You can see the minimum run length steadily falls as the cycle rate increases. For example if your cycle rate

is fifty dozen per hour and you improve to 60 dozen per hour, the minimum run length drops from 652 pieces to 525 pieces.

Reduction in setup time, and an increase in cycle rate is the best way to reduce the long run minimums with a fixed break

even.

Variable Cycle Rate

To Achieve Minimum Run Length

1000

2000

3000

4000

5000

30 40 50 60 70 80 90

Cycle Rate In Dozen Per Hour

Min. Run Length

Figure 6.32 This graph illustrates the

impact of cycle rate on the minimum run

length with a fixed break even point of

$0.79 and a fixed setup changeover time

of forty-five minutes. The results are only

appreciable at the slowest ends of cycling.

After fifty dozen the change in cycle rate

makes a negligible change in minimum

run length.

PAGE

. 27

Be sure that your shirt detec-

tor is functioning as the non-

human part of the safety net.

Begin loading at thirty dozen

per hour. Gradually take it to

forty then fifty then sixty and

at seventy dozen per hour you

have hit a plateau. Turn the

press back down to forty

dozen and have your top

loader stand back and just

watch.

Within hours most trainees

can load at speeds up to sev-

enty dozen per hour. It gives

your top staff a break and

you an increase in productivi-

ty as well as capacity.

Resource

Allocation And

Dependencies

There are dependencies in

this and all other manufacturing operations. It means that there must be a spe-

cific sequence and if the process is taken out of sequence, the results will

appear to be random and the process will be said to have too many variables.

If you address subsequent variables before you have a solid foundation, your

results will be futile, they will not last. For example if you set a tension level first

in the chain of events, you are able to print but all other elements must be

skewed to fit the tension level. If you pick and ink before you have standardized

your operation, you may never know if the ink or something else causes trouble.

Most practitioners know what to do but the secret to success is to do it in the

correct order. We have listed a logical and simple sequence to be followed and a

description of these rudimentary steps is given in the side bars on the following

two pages.

Costing

Run your presses faster by following these steps:.

1. Calibrate press and flashes.

2. Use thin, flat large open mesh.

3. Thoroughly dry and expose

screens.

4. Find low tack shear thinning ink

with minimal plasticizer.

5. Run sharpened blades at top

speeds monitor slowest head.

6. Spray minimum tack sprayed at

central area only.

7. Insure adequate line-air pressure.

8. Minimize stroke length.

9. Optimize flow controls on lift

cylinders.

10. Use Ends Caps on flash jobs and

long runs.

Running The Press Faster

How To

Instructions

PAGE

. 28

DDeettaaiillss OOff DDeeppeennddeenncciieess

Comprehensive explanations of virtually all of these stages

and steps are included in this manual. We encourage you not

only to review its contents but be sure that all involved parties

in your organization do the same.

1. Calibrate the press.

a. Parallelism.

b. Clearance.

c. Tolerances.

The planes of the carriage travel, the screen mesh and the

platens must be parallel. Otherwise it will be impossible to

produce a predictable, consistent print. A detailed step-by-step

procedure is listed in chapter six. Clearance must be proper

between the screen and the screen holders and they must be

plumb for proper off-contact settings. The tolerances of the

Gauntlet and Challenger presses will allow you to print butt to

butt register or 150 line halftones at top speeds.

2. Gauge image tolerance.

a. Press accuracy.

b. Press repeatability.

The press and printing variability must be within the dimen-

sional tolerances of the image. Image tolerance can be identi-

fied with a loupe, mathematically or by gauging the art in the

computer before it is output. Chapter one reviews the toler-

ance of the image, screen and tensioning. The Gauntlet and

Challenger presses lock into preset cam followers at three

points on the carousel, insuring exceptional registration. The

drive and shock assemblies are designed to allow you to

smoothly register for years to come. None of the balance of

the process can compensate for an erratic press but if yours is

M&R there is no need to worry.

3. Establish off-contact distance.

a. Maximumreproportioning.

b. Minimumimage stretch.

c. Mandatoryuniform ink transfer.

Once the press is set and the tolerances determined you would

1. Calibrate the press.

a. Parallelism.

b. Clearance.

c. Tolerances.

2. Gauge image tolerance.

a. Press accuracy

b. Press repeatability.

3. Establish off-contact distance.

a. Maximumreproportioning.

b. Minimumimage stretch.

c. Optimumuniform ink

transfer.

4. Select screen mesh.

a. Registration

b. Ink transfer.

c. Aesthetics.

5. Support off-contact distance

with screen tension.

a. Balanced elongation.

b. Square opening.

c. Below elastic limit.

6. Select stencil.

a. Durability.

b. Transparency.

c. Dry time.

7. Process the stencil.

a. Resolution.

b. Edge acuity.

c. Ink transfer.

8. Process films.

a. Transmission contrast.

b. Resolution.

c. Dimensional stability.

9. Select test squeegee blade.

a. Standard angle and pressure.

b. Length, width, height.

c. Edge to suit mesh.

10. Set squeegee blade.

a. Minimum deflection.

b. Total ink transfer.

c. Zero image stretch.

Chapter 6

oduction S

eps

PAGE

. 29

set the off-contact distance. As detailed in chapter six, the

proper off-contact distance creates uniform ink transfer, and

insures the dimensional accuracy of the image. This distance

must be the first setting on the press. The constraints to off-

contact distance are an upper limit where the printed image is

larger than the original. The lower limit is where the image is

stretched in the stroke direction. And it is mandatory that the

off contact is sufficient to insure uniform ink transfer, tension

alone cannot usually accomplish this.

4. Select screen mesh.

a. Registration

b. Ink transfer.

c. Aesthetics.

The screen mesh (discussed in chapter two) has a fundamental

responsibility for image registration but tighter is no insurance.

The shift on press and many imaging problems are due to the

S-S balance of the fabric, in its virgin state and on press. In all

cases you will want to select plain-woven low elongation fabric.

Screen mesh is the primary determinant of ink transfer and its

geometry should be thin and open. Aesthetically you need a

level of opacity or transparency, a degree of smoothness and a

specific volume of ink. The mesh sets the stage for all of

these facets. Note that the mesh is not selected for a presumed

tendency to insure image resolution.

5. Support off-contact distance with screen ten-

sion.

a. Balanced elongation and square opening.

b. Sufficient to encourage ink transfer.

c. Below elastic limit.

Screen tension is required to permit the off-contact distance

set above (Refer to chapter one for details). The S-S balance of

the fabric will permit stable tension and a square opening if

your methods include tension by percentage of elongation.

The tension must be at a lower limit to encourage ink transfer;

it cannot create a uniform transfer in most cases. It has an

upper limit of an elastic limit that should be respected

11. Maximize press speed.

a. Minimum dwell.

b. Fast blade speed.

c. Minimum stroke length.

12. Calibrate flash.

a. Accommodate press speed.

b. Minimum temperature.

c. Minimum distance.

13. Optimize dryer.

a. Adequate for press output

b. Below remelt temperature.

c. Energy efficiency.

14. Select ink by properties.

a. Optical.

b. Rheological.

c. Thermal.

d. Physical.

15. Request a CofA.

a. Identify status quo.

b. Communicate to ink maker.

c. Anticipate improvement.

16. Temporarily adjust to accept

ink deficiencies.

a. #10 (pre-production steps).

#1 (production steps)

#2 production steps).

#3 (production steps).

17. Provide proper labor.

a. Quantity.

b. Skill sets.

c. Orchestration.

18. Assess costs and selling price.

a. Conversion costs.

b. Raw material costs.

c. Fixed costs.

19. Reevaluate ink when ready.

a. Temporarily adapt.

b. Repeat process.

Costing

oduction S

eps

PAGE

. 30

6. Select stencil.

a. Durability.

b. Transparency.

c. Dry time.

The properties of the stencil

that is best for your operation

should include durability for

your press, flash units, and

ink chemistry. It should be

transparent to assist in regis-

tration or adjustments on

press. These two directly

influence the press operation.

Finally it should dry quickly

since as much as 70 percent

of the stencil processing time

is drying. Note that resolution

is not included as a variable

here. As chapter two will

detail, the demands of most prints are met and exceeded by the resolving power

of most coatings; it is the processing that ruins the results.

7. Process the stencil.

a. Resolution and edge acuity.

b. Durability.

c. Ink transfer.

Your tools, coating methods, level of dryness, exposure and washout will all

impact the resolution and edge acuity of the image (Refer to page ___ for

details). All of these also affect the durability of the stencil and this directly

causes or prevents interruptive downtime. The stencil should be seen as a

metering device to establish the width and height of the image but to establish

its thickness as well.

8. Process films.

a. Transmission contrast.

b. Resolution.

c. Dimensional stability.

There is a measurable density of films from 3.0 to 5.0 to block out the actinic

Chapter 6

The best way to staff a press for production

efficiency follows:

1. One person at load position.

2. One person at unload position.

3. Rotate loader and unloader every 20 min-

utes.

4. One person to caddy (see page 6.8).

5. Rotate caddy to load/unload positions

every four hours.

6. One person at dryer.

7. Rotate dry person to load/unload position

at end of shift.

Staffing The Press

How To

Instructions

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