Mar 06 2008

Molders, We’ve Never had it so Good!

Published by at 12:52 pm under Uncategorized

Many of the experts in out plants talk about the Good Olde Days trying to impress the Newbies on how they gained their experience.  When viewed with a skeptical eye the Good Olde Days weren’t, and today (albeit the old pros are loath to admit it) the molders of today actually have it pretty good.  Brent Borgerson tells us about his experiences. Molders generally complain a lot less than do people in other professions, but once in awhile, they let loose. When I hear the younger Molders complain, my mind harkens back to the time when I first began molding, or maybe better said, when I first tried to mold.

In the summer of 1968, I first stepped into an injection molding plant. In those days, it was customary to hire young people for summer help. This was both for covering vacationing workers and to help teens with summer jobs. I was assigned to third shift, and worked for 3 sets of Christmas and summer vacations, when home from college. I was a hopper filler and operator. The Foreman asked me after the third year what I was going to do after college, and then offered to show me molding, until I found out what I wanted to do with life. The owner and big shots didn’t want to waste time on me, since in those days, “college kids” didn’t go into or stay in injection molding. My boss prevailed though, and in 1970, I began my life-long study of injection molding.

This shop had about fifteen presses; six were HPM presses, with hydraulic clamps that had been converted from plunger presses to the relatively new Egan reciprocating screw plasticizing/injection unit. There were assorted Lester, IMPCO (mono-toggle), and a battery of Husky molding machines. The injection units of the Husky and IMPCO presses was a screw feeding an injection plunger, so no non –return-valve screw tip was needed, and the Husky presses were mono-toggle as were the IMPCO presses. The Husky toggle rode in a constant bath of gear oil and was powered by electric motors connected to V belts. Who says the electric molding machines and Sodick- Nissei injection units are new?

The Husky press clamps were controlled with cams and micro switches. The cams rode on a shaft that resembled a distributor (remember them?) shaft on an auto, and the housing was like a big automobile distributor housing with many contact points. Setting the clamp and lockup was a real art and it was easy to lock past center, then it was hell to open up. Maybe you could crank the clamp open with a big breaker bar and pipe, maybe you could attach eyebolts and chain to the toggle and yank it open with the fork lift that was used to set molds (who had overhead hoists?), but sometimes you had to cut the tie bar nuts off with a torch!. You didn’t argue about scientific molding with these presses as there was only injection speed and pressure. You had to be careful when working in the mold space, as when the motor stopped, the clamp would drift shut and pinch you or worse.
The IMPCO presses had a heavy vertical mono toggle, and only a known- to –fail hydraulic check valve to hold the clamp open during mold changes. You learned to put 4×4 timbers between the T slotted platens when changing molds as there were urban legends (or were they legends?) of the check valves failing and the platens slamming closed on unsuspecting die setters, as mold setup people were called in those days. Both presses had nozzle shutoff valves that leaked plastic all over the place. The Husky had opposing concave washers that were compressed to open by the traveling front platen that was moved by the rear platen. The IMPCO had a hydraulic nozzle shutoff. Both presses ran only olefins, but those Husky could run four second cycles, even in those days. At least with the Huskies, you didn’t deal with oil leaks.

Just about all hydraulic presses were “bleeders” in those days. Some presses were put inside sheet metal pans in an attempt to stem the tide of oil; those would then “walk” across the floor due to vibration. Brand new presses leaked oil; we had to send back a spanking new Farrel press due to daily leaks that couldn’t be solved. We expected it on the old presses but a new one? Those converted HPM presses were really bad, they had steel hydraulic lines going everywhere and you could see them vibrate like guitar strings as the press went through its functions. Compression fittings needed constant tightening, and lines broke at least once a shift. It seemed that the lines with the most intricate bends were the ones that broke the most. Steel tube bending quickly became a learned skill. Major tank-emptying oil leaks were common.

Hydraulic filtering in those days was crude, mostly consisting of a suction screen in the tank that would catch things like the rag or screwdriver that fell into the oil drum, but not do anything to protect the hydraulic systems whose only saving grace was the large clearances in the valves. Valve changing was a constant chore, as was 110V solenoids burning out. When was the last time you changed a valve? Sometimes you just lapped the valves and slapped them back on (now why is that process so unstable?) and were back in production. Pump failure and rebuilding was frequent, I don’t think I remember how to rebuild a hydraulic pump.

I thought that maybe we were the only ones that bought “Oil Dri” by the skid, but as I worked part time in other shops, I found out that this was industry standard. One place in Chicago stood the operators on skids to keep them out of the oil. I worked in a thermoset place that had the area’s first Hunkar process controller. It was on a big NATCO press that had a cracked clamp cylinder housing. A trough led the leaking oil to a barrel and then it was pumped to the overhead oil reservoir of the NATCO. I thought it was a temporary fix, but learned that it had been there for five years, fifteen years later, I learned that the press was still like that.

Controls on the presses were crude and problematic in the “good old days”. Each press had a control cabinet that was often as big as the press. Every function was controlled by a series of relays with multiple contacts to burn, and stick (I’ve seen troubleshooters kick the cabinet to get the press going again) and multiple wires to break, and they did, often. You had timers for: clamp closed, clamp open, boost, and 2nd stage injection. People didn’t transfer by position then. The timers would stick and were not very repeatable. Some timer functions were accomplished by pneumatic time delay relays that would develop perforations in their diaphragms. Heater band control was done by West type mirrored heat meters or percentage rheostat control. PID? What is that? Mercury contactors were in the future and heat relays often stuck with disastrous results

In the late 1970’s we installed among the first cavity pressure controllers from Control Process Incorporated (CPI) then owned by Rod Groleau who later founded RJG Associates and Don Paulson, who later went into training. The concept was great; a quantum leap from booster timer to cavity pressure control, there was a company whose instrument actually went into the housing that was for the boost timer (SCI). Though transducers were expensive and fragile, the real problem was that the hydraulic systems couldn’t respond to the cavity pressure controller fast enough. Process graph recording was done on pressure sensitive paper.

Process were not stable, breakdowns frequent, and Molders those days wore big tool pouches on their belts as you had to hop from machine to machine to deal with the problems. Fiddling with the process was chronic and frequent, and molding was more of an art than a science. I went to the boss with a problem and he would reply with something like; “ give it a skosh more pressure” or “take off a tad of feed”. Feed was shot size. Scrap rates were, by today’s standards astronomical.

Molds too were crude by today’s standards, and flash trimming and fixturing were accepted practices.

The importance of coolant flow was not recognized back then, and if you wanted a quicker cycle you put a portable chiller on the mold and ran it cold enough to form ice on the lines. Ethylene Glycol was used, even in central systems to keep from freezing the compressors. EPA? What EPA? Who cared if it was a slippery mess on the floor?

This brings us to safety. The standards and practices then were lax. A Molder’s experience was often judged by missing digits on their hands. OSHA hadn’t come into being and molding machine and auxiliary equipment safety features were not very sophisticated at all. Even if the rear gate limit switch wasn’t tied down, there were open areas where a person could put their hand into. Clamp areas were open, even on toggle presses. Mechanical safety bars were “nutted” and if the open position was changed, they were rendered useless. .Self-adjusting safety jam bars were in the future. SPI safety standards were evolving yet, and safety education not generally emphasized as it is now. Right to know was unheard of then. Production was everything. I remember shutting down a dangerous new assembly machine twice when I was a 3rd Shift Foremen. “They” (upper mgmt) threatened to fire the whole shift, including me if we didn’t run the machine. That night a girl got her finger torn off in it. It took Maintenance 2 hours to fashion a guard. I witnessed some horrible accidents before I studied Industrial Engineering and Business Management, and became less ignorant, and went to a forward thinking company.

Speaking of management, the styles back then were of constant yelling and threatening, there was much tension and aggression in the workplace. Cleanliness and quality were not stressed as they are now. Comfort for the worker was not emphasized as it is now. Rare was the molding room with air conditioning, or even good ventilation and a water cooler.

“Back then”, there was no internet, few institutions of higher learning teaching injection molding, and few seminars and magazine articles available. Paulson was just starting in the 80’s and another pioneer in the field was my mentor Bill Tobin with his seminars and his monthly “how to” articles in a trade journal that I think was titled Plastic Machinery and Auxiliaries. These series of articles convinced me to stay in molding. Educational opportunities were limited then. You were lucky if a good molder took you under his wing. Many didn’t want to share their “secrets”.

When we now look at the reliability of the equipment, the evolution of the science of injection molding, working conditions, educational opportunities and modern management philosophies, it is easy to see that we molders never had it so good and that the good old days were not really so good.

Brent Borgerson
Matrix Tooling/Matrix Plastic Products
Wood Dale IL

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Now you can comment or add your experiences to this story.  We’d welcome it.

One response so far

One Response to “Molders, We’ve Never had it so Good!”

  1. WJT Associateson 08 Sep 2014 at 1:41 pm

    please contact me directly and I’ll send you what you want.


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