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December 1, 2001

7 Min Read
Materials Update

Why all these resins? 

Editor's note: Consultant Bill Tobin of WJT Assoc. is a regular contributor to IMM and here takes a look at material bundling as a way to reduce the number of different resins being stocked. 

I recently taught a seminar on productivity. One owner of a shop said he had to maintain more than 300 resins, grades, and colors to service all his clients. While this is difficult, he said this is what his clients want so that's what they get. 

We can assume the 80-20 rule in this case means 20 percent of these 300 resins are probably consumed 80 percent of the time. The math shows there are 60 prime resins, grades, and colors that are consumed often, while 240 are used only occasionally. 

What are the implications of a huge inventory of different resins? 

First, you have essentially turned into a bank that constantly loses money. You might buy 500 lb of Magic Plastic's brand of SuperHot Gee Whiz ABS because the customer specified it. However, you paid a high price for such a low volume. Further, you probably didn't use it all, and the rest sits in storage. 

The second implication of a large amount of different resins is laziness. Your customer has switched materials, the job has been retired, or the mold has moved and you didn't realize how many bags of material associated only with that job are in your warehouse. When your customer switches materials, no longer orders parts for the customary two years, or moves the mold to another vendor, part of the cost of any of these activities is the material you have on hand dedicated to his production. 

The third reason for holding a lot of different resins, unfortunately, is the resin companies themselves. Some will go to your clients and chat them up about how they can make a resin to fit one particular need. Often the designer and material sales rep cook up a customized material specification. However, once you've chosen a single-use material, sole manufacturer, and his grade, there is no equivalent. 

What was the design intent? Heat resistance, high melt flow, strength-to-thickness properties, chemical resistance, plateability? If, as a molder, you go back to your client and find out exactly what he wants, what you often discover is that there are many materials that can fill the need for the product. 

With all that in mind, here's the game: It's called bundling. What if you could buy in 40,000-lb truckload lots instead of more than 20 sets of a few bags each? Obviously your per-pound cost would drop dramatically, and your inventory turns would increase. 

The first step on the road to bundling is to get away from special requirements.

How Do We Bundle? 
The first step in bundling is to get away from the special requirements and see if the general purpose grades work. Usually they do. Talk your clients out of buying precolored materials in favor of color concentrate. Use color concentrate with proportional blenders mounted on top of mini hoppers at the machine. Your major inventory then becomes un-mixed virgin. If possible, always have a product that is black. This is where most of the regrind of the precolored material goes. This also makes a place for off-color material. 

Bundling, as the name implies, is the collecting of one grade of resin for multiple clients and buying with economies of scale. Your pricing to your clients, however, should not be a direct pass-through of these savings. Each job must stand alone because it is the group that made the savings. If the group falls apart there are no savings. You can develop a competitive advantage by passing a percentage of the savings along. Since most jobs comprise a relatively low percentage of machine cost and a high percentage of material, this will make your price very attractive. 

Still, trying to get a material change out of a customer who is happy with what he has is like trying to herd cats. It can be done but it's extremely difficult. Point out to your customer's purchasing agent that bundling lowers the price. Sell the buyer on the concept, and he'll do most of the work for you. Also, realize that not only are specialty or precolored resins expensive, but also the customer is at the mercy of the resin company when it comes to price. Horror stories abound when some of the major resin companies have announced they will no longer produce a specialized grade, or the price is going up by 30 percent. Their clients are left to scramble for another source or eat the pass-through increase. 

As Wall Street continues to dictate the profits required by major manufacturers, you will see the resin supplier's catalog of grades drop back to where it was 20 years ago. There will be a few general purpose resins with lower costs, but, unfortunately, most will likely stay at current levels. Custom resins will become hard to find, hard to specify, and pricey. If you start now, you'll be ahead of the guy down the street. The key to competition is to let the other guy put himself out of business while, at perhaps the same price to the same clients, you make a profit. The only real difference is how well you play the game of business. 

WJT Assoc.
Louisville, CO
(303) 604-9592
fax: (303) 604-0319
[email protected] 

1201i48a.jpg Clear resin complements pristine water
In search of a clear material to accentuate the purity of the water in its purifier, Fantom Technologies selected a copolymer for use in the Calypso Microbiological Water Processor's clear treatment chamber and clean water carafe. Eastman's Durastar copolymer was chosen for its toughness and ability to withstand the rigors of ozone exposure. The final color, clarity, and gloss of the finished product were also important considerations. 

The material has no halogen-containing compounds and produces no toxic substances when properly incinerated. These characteristics, combined with fast cycle times, reportedly make it a good choice for injection molded clear appliance parts, point-of-purchase displays, and toys. 

Eastman Chemical Co.
Kingsport, TN
(423) 229-1624

Licensing agreement for PHBH announced 
A new biodegradable, bio-based plastic is the subject of a licensing agreement between Procter & Gamble and Osaka, Japan-based Kaneka Corp. The agreement is for the initial commercialization of PHBH. Kaneka holds composition of matter patents while P&G holds several patents covering the processing and application of the plastic. Under the agreement, Kaneka will complete the application and processing of the plastic and will develop the commercial manufacturing process. The companies expect to produce a significant quantity of PHBH commercially within three years. PHBH will join P&G's Nodax portfolio, which comprises a new family of related biodegradable, bio-based plastics. Applications include personal hygiene products and medical devices. 

Procter & Gamble Co.
Cincinnati, OH
(513) 983-6678

Engineering resins selected for sport recreation vehicle 
Hoping to enhance the look and safety of its vehicle instrument panels and knee bolsters, General Motors Corp. sought out two engineering thermoplastics from Bayer for the 2001 Pontiac Aztek, coined the industry's first sport recreation vehicle (SRV). Bayblend PC/ABS resin and Lustran ABS resin were chosen for their ability to meet the coloring, contour, and temperature-resistance needs of the Aztek. 


Lustran Elite HH (high-heat) ABS 1827 resin from Bayer was selected to shape the instrument panel cluster, end caps, radio trip plate, and forward extension defroster grill. GM wanted to add flakes to the instrument panel to contribute to the distinctive appearance of the vehicle, and this resin was a viable choice due to its ease of coloring. Impact resistance, toughness, processing ease, heat-resistance, and dimensional stability were also desired characteristics. The instrument panel cluster is 18 by 30 inches, while the radio trim plate measures 15 by 12 inches. Both parts are 9 inches deep. The thinner end caps measure 10 by 8 by 1 inch and the forward extension defroster grill is 13 by 50 by 2 inches. 

For the driver-side knee bolster and glove box assembly, GM chose Bayblend T 85, a general purpose PC/ABS blend. This resin is said to provide good impact strength, eliminating the need for metal reinforcement. It was also selected for its ductile failure properties, which help increase the safety of drivers and passengers during an accident. The driver-side knee bolster is composed of two separately molded pieces, each measuring 9 by 20 by 2 inches and featuring molded-in ribs for improved structural integrity. These pieces are attached via vibration welding. The glove box assembly is composed of three separately molded pieces, including 10-by-14-by-1-inch inner and outer parts and the glove box bin (12 by 20 by 15 inches). 

All parts were molded at Meridian Automotive Systems in Dearborn, MI. Bayer provided computer-aided design (CAD) and finite-element analysis (FEA) for the molding process. 

Bayer Corp.
Pittsburgh, PA
(412) 777-7419

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