I enjoyed manufacturing engineering early in my career at Square D, Inc. My first task was to write and illustrate documentation of manufacturing processes in support of ISO 9002 certification. I showed an interest in solving a long standing problem, terrible throughput making their auxiliary logic cartridge, and they allowed me to work on it (the Logic Cartridge project below). After the summer they allowed me to continue part time, and then full time after graduation.
I had oversight of four lines including the highest volume product at the plant (because the women running it were very sharp and needed little help). My duties were trouble shooting and cost reduction. I was also angling for a job with their automation group, but Square D was bought by Schneider Group and employment was frozen.
While working for Eaton Corporation as a product design engineer, I was often engaged with the manufacturing efforts where I:
I had oversight of four lines including the highest volume product at the plant (because the women running it were very sharp and needed little help). My duties were trouble shooting and cost reduction. I was also angling for a job with their automation group, but Square D was bought by Schneider Group and employment was frozen.
While working for Eaton Corporation as a product design engineer, I was often engaged with the manufacturing efforts where I:
- Wrote and reviewed process documents.
- Performed internal audits for ISO 9002,
- Assisted QA on troublesome issues (see the Sump Pump switch information),
- Resolved problems with molds wearing out,
- Selected and proved out new materials for cost reduction.
Auxiliary Logic Cartridge (ALC) for X-Relay
The main problem with the ALC was poor assembly throughput, and a lot of scrapped product. The ALC was low volume, offered as a line completer so that old school relays could signal to newer digital systems. They offered standard metal contact cartridges, but for digital (dry circuits) these reed switch units were more reliable. The relay would slide a small magnet carrier within the ALC towards the reed switch to close it, and slide it away to open it. Reed switches have a natural hysteresis - you have to pull the magnet farther away from the switch than the point where the the magnet causes contact closure. This hysteresis must be within the small range of motion provided by the X Relay. The ongoing problem was the switches would close, but never release. When the one associate who was able to get them to work went on maternity leave and there was no one able to make functioning parts. Even the heroine had been able to get only 1 in 10 to pass the functional test. Her method had involved trying to trim the moving magnet to weaken it. But when the switches would release as needed, then the reeds would not pull in at the correct location. After some time reading supplier literature, and scratching my head, I had one of my first engineering "ah-ha" moments - I realized that the iron leads of the reed switches were simple too long. They made the magnetic flux too dense when the reeds came together. Cutting the leads very short made assembly, without resorting to bias magnets, nearly fool proof. X-Relay Auxiliary Cartridge Printing Cost Reduction. I worked to improve pad printing of auxiliary contact cartridges (poor legibility). Performed a study and recommended an upgrade path to solve the problem. Set up pneumatic tools. NEMA SIze 1 Motor Starter Timer Performance and Thermal Safety The Size 1 motor starters had a long list of optional features. I worked resolving problems with the timer, a reservoir of air that would leak down to trip and latch the starter open or closed, and with the thermal overload release (solder that melts from electrical overload causing the contacts to open). Explosion Proof Enclosures I monitored this product, but nothing came up during my tenure. Good associates on the factory floor are a real plus. Zenith/Square D Panelboard Lighting Contactors contact Spring Quality Issues These 200 to 600 Amp contactors were designed in a low profile configuration to fit in electrical enclosures that had little extra depth. Used primarily for large arrays of incandescent lighting such as parking lot lighting. A special characteristic of incandescent lighting loads is their tremendous inrush current when closed. Mechanical switches will bounce for a few milliseconds and the resulting arcs can quickly destroy the contact surfaces. The springs that provided compliance when the contacts closed had to be matched for spring force. There was an ongoing problem that the springs supplied would not pass the final testing. I re-purposed a Chatillon scale and built a fixture for checking the supplied springs so only matched sets would be used in a particular contactor. Unfortunately, I have no souvenirs of this effort and it seems to be a defunct product line (not many incandescent lamps in use for flood lighting in large arrays). |