smed tips
TRANSCRIPT
some bad. Here are a few of the lessons I’ve learned: 1) Scales should be either met-ric or, if inch, decimal. Most inch scales are in fractions of an inch and can be hard to read. Even when read cor-rectly, it can take time to figure
out which line represents 10-9/16. Oregon Rule has a wide va-riety of scales pr inted on plastic film with an adhesive backing. Their scales are available in
decimal inch as well as metric. 2) In most setup applications, the scale is not measuring any-thing. It is simply a number to match the pointer too. If possi-ble, standardize all scales to use the same gradations, ei-ther inch or metric. 3) Perhaps the biggest prob-lem I see with the use of scales
Those of you who have been to my workshops, read this newsletter or know me at all know the tremendous impor-tance I place on making pre-cise changeover settings. Ex-actly! Is the fourth component of the ESEE methodology. This month I want to talk us-ing scales or rulers in setup. A scale is a piece of metal or plastic that is divided into s e g m e n t s . Markings may be inch, metric, degrees or arbi-trary units. When used in setup, the scale is affixed to a stationary component of the machine and with a pointer on the adjustable component. Or vice-versa. They are a simple and effective way to put preci-sion into an adjustment if prop-erly applied and used. I’ve seen a lot of applications over the years, many good,
SOME THOUGHTS ON… SCALES & POINTERS
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August 2010
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is the pointers. One manufacturer puts a very nice scale on all their machines for height adjustment. However, there is no pointer, making the scale little more than a decoration. Another popular machine uses a square steel tube running the length of the machine to mount clamps. The bar is nicely etched with a scale but there is no indication of which side of the clamp is to be read. A simple punch mark solves this problem.
4) I’ve seen a machine with an adjustable pointer. Pointers must be rigid and fixed in position. If they move, their whole point is lost. 5) A fairly common problem is that the pointer is not close to the scale. This causes
reading error due to parallax.
The scale is only half of the tool. The pointer is the other half and every bit as important. 4) Scales are only as good as their calibra-tion. The appropriate scale reading must be determined for each product and setup. This then needs to be documented and made available to the mechanic or operator. If they don’t know what the value is, they can’t set it. 7) If only a few products are normally run, custom scales can be used. One plant with 6 different products mounted metal strips with a mark for each product size. The pointer has a slot in it. All scales (as well as all other setup adjustments and changeparts) are colorcoded. In setup, the appropriate colored mark is centered in the
pointer slot. In this plant the operators do not even need a setup sheet. They simply set everything to green Scales are a valuable setup tool, in part be-cause they are so simple and straightfor-ward.
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SOME THOUGHTS ON… (cont)
© Copyright 2010 by John R Henry, all rights reserved. Permission is granted to copy and circulate this newsletter provided that it remains intact. For permission to republish articles in other venues, contact [email protected]
Page 3
SOME THOUGHTS ON… (cont) This simplicity can work against them by causing peo-ple to take them for granted. Are your scales all they can
TIP OF THE MONTH.. . MAGNIFYING POINTERS
A few months ago I had pointed to the Saw Stop as an interesting safety device. For those who don’t remember, this is a device that instantly stops a circular saw blade on contact with a finger or other body part. If you want to know how in-stantly, check out the video us-ing a sausage to simulate a finger. http://sawstop.com/howitworks/how_overview.php In a recent discussion in my Changeover/SMED group on LinkedIn, someone had men-tioned magnifying pointers. This is a plastic piece with a lens molded into it. Across the center of the lens is a hairline. The lens embiggens the scale making it easy to read the markings. The hairline is on the back, reducing the possibility of parallax error. I had asked for pictures or
sources but the only place we have identified so far is on the Saw Stop machine. You can see it in the video "ICS Product features" at the Sawstop site. They use it for precision setting of the rip fence. I have not contacted Sawstop yet but I would imagine that the lens is available from their parts department. I suspect that it is commercially available in this and other con-figurations but have been searching and cannot find it anywhere. Does anyone know where it might be purchased? If so, drop me a note at [email protected] so I can share the info here.
John Henry’s Lean Changeover Newsletter See more & subscribe at www.changeover.com
© Copyright 2010 by John R Henry, all rights reserved. Permission is granted to copy and circulate this newsletter provided that it remains intact. For permission to republish articles in other venues, contact [email protected]
What do you think? Please let me hear from you at [email protected]
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be? Don’t let this valuable tool be anything less.
John Henry’s Lean Changeover Newsletter See more & subscribe at www.changeover.com
August 2010
www.changeover.com 787-550-9650 [email protected]
A. Changeovers per week (#) B. Changeover duration incl. startup (min) C. Downtime cost per hour ($) D. Changeover cost per week (A X B X C /60) E. Changeover cost per year (D X 50) F. Annual savings per minute of changeover reduction (A X C/60 X 50)
A. Changeovers per week (#) B. Changeover duration incl. startup (min) C. Downtime cost per hour ($) D. Changeover cost per week (A X B X C /60) E. Changeover cost per year (D X 50) F. Annual savings per minute of changeover reduction (A X C/60 X 50)
EXAMPLE
A plant performs 1 changeover per day taking on average 2 hours each
Assumes 5 day week, 50 weeks per year
A. Changeovers per week (#) 5 B. Changeover duration incl. startup (min) 120min C. Downtime cost per hour ($) $10,000.00 D. Changeover cost per week (A X B X C /60) ( $100,000.00) E. Changeover cost per year (D X 50) ($5,000,000.00) F. Annual savings per minute of changeover reduction (A X C/60 X 50) $41,666.67
A. Changeovers per week (#) 5 B. Changeover duration incl. startup (min) 120min C. Downtime cost per hour ($) $10,000.00 D. Changeover cost per week (A X B X C /60) ( $100,000.00) E. Changeover cost per year (D X 50) ($5,000,000.00) F. Annual savings per minute of changeover reduction (A X C/60 X 50) $41,666.67
You know changeover is expensive but do you know how expensive? See how many dollars per year even a 1 minute reduction in changeover time is worth. Use this changeover calculator below to calculate how much changeover costs your company. Sim-ply enter the relevant numbers for your plant in A, B & C and do the math for D, E & F. The numbers will shock you. For a self-calculating Excel spreadsheet e-mail [email protected] Start cutting these costs NOW! Call John Henry at Changeover.com 787-550-9650.
“If not now, when? If not you, who?”