Nov 11 2011

A new Buzzword COMMON SENSE

Published by at 3:07 pm under Uncategorized

While I’m all for LEAN, SMED, JIT and all the buzz-words/multi-letter acronyms there’s an interesting argument for common sense.

LEAN is good, because it is designed around eliminating waste, and understanding profit. There are four principles of LEAN

  1. Improve Quality
  2. Eliminate the Seven Types of Waste
    1. Unnecessary movement of materials
    2. Excess inventory
    3. Inefficient Layout
    4. Waiting
    5. Over production
    6. Rework / reprocessing
    7. Defects
  3. Reduce the time it takes to finish an Activity
  4. Reduce total Costs

What’s interesting here is all four principles are based on the definition of an acceptable part. Here is where Common Sense must prevail:

Do you and your customer have a crystal clear definition of an acceptable part? How many times has a gate mark been both acceptable (because they needed the parts) or unacceptable (because you fell for the specification “no manufacturing / visible defects”)?

In molding there’s usually little need to ‘improve’ quality. However there’s a screaming need for a fixed, uncompromising, unchangeable definition for acceptable parts that is clearly defined and understood by you and your customer.

* *

SMED or fast changeovers come in two steps:

The first is purely mechanical. Is the new mold scheduled? Do you have all the accessory equipment and people available for the next run? Do you KNOW how to hook up the water and set the process conditions? Is the mold ready to run acceptable parts or is it out for maintenance and nobody told scheduling? Is the setup team/crane/forklift available when the job is ready for changeovers? This requires PLANNING by everyone. Not just an edict from a computer or a schedule.

The second in many instances conflicts with the ‘reduce total costs’ philosophy. The fastest way to begin running a new job is either to be able to use the same material as the previous run OR have a separate portable dryer that has pre-dried the material so you don’t have to wait. Do you have enough of these portable dryers available or do you need to buy more?

While there’s a lot to be said to comparing a mold changeover to the pit crews of NASCAR, if you don’t have useable material it doesn’t matter how quickly you changed the mold. The same is true if your setup team is troubleshooting another machine and ‘couldn’t get around to it’ because their first priority was to keep production running.

* *

Reducing the ‘time to do an activity’ and JIT are based on an interesting assumption: loading.

If your shop is under-loaded, idle equipment becomes an expense. There’s only so much you can do to fill up your capacity.

I’m embarrassed to say our capitalist system views people as an expense. We try to keep wages low when we should be looking at how much does each individual contribute to the profit (People Loading). Paying two people who can do the work of three or more at the same wage as a slacker explains why you lose your best people.

Training those who could contribute more is usually last on the list for available money, while ‘Lack of Operator’ is a shamefully common excuse for idle time. Cross train your people. Who says someone who is an operator can’t help hook up waterlines, or do the first few steps in troubleshooting? Spending a few thousand to train everyone in the principles of good molding, troubleshooting, mold changeovers, even driving a forklift; will pay back many times over even if only a two out of twenty apply it. New people create scrap. Retention of good people, periodic training of everyone (new and old), and rewards for the ‘players’ will keep your operation Lean and costs low.

JIT and SMED are based on a mystical assumption that if you reduce the changeover time to nothing (from the last good part to the production of goods parts for the next run) the unit cost of a ten part run is the same as the unit cost of making a million parts. PLEASE NOTE: I didn’t define SMED as only changing tools. This has to be a measure of the cost of idle time between two different saleable parts. When trying to cram this philosophy into a high volume industry like injection molding where a mold might be changed in fifteen minutes but a good part will be consistently produced after an hour of ‘dialing it in’, is false thinking. Once you understand how to change molds quickly; learn how to start them up equally fast.

The big ‘sales point’ to JIT is the lack of storage costs. Good thinking on the part of the customer; what about the molder? There are some easy to use Economic Order Quantity formulas available from any economics text book or the internet. What you quickly find is that while perhaps you shouldn’t make two runs per year for a customer when you ship weekly, you might make more profit is you made six or eight. What’s the cost of storage? If you have an international freight container in your parking lot and use it as a warehouse, what do you think the cost is per cubic foot?

* * * *

At the end of the day we’re all here to maximize profits with minimized expenses. While people with letters after their names expound on the individual components of LEAN, SMED, and JIT what you have to ultimately look at is a simply philosophy: “In the Big Picture, what gives the most profit?” Toyoda’s principles are neither academically technical nor complex. It isn’t about precision, it’s about consistency. It’s not about automation; it’s about properly using what is necessary whether it’s a robot or a person. More importantly, it’s about common sense.


Bill is a trainer in molding, a consultant and a writer. You can contact him at

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