Plastics Fabrication

why do plastics have such a bad rep? Who is defending our industry, and how can they do better?

PLASTIC A BAD RAP. where do you get this information.

please, if you are an informed (heck you don't even have to be informed) consumer, vendor, OEM. Take away plastic and its derivatives, were would you be. Try living in a cave. Which is pretty close to the truth, of where one would be.

Stop crying. you have to defend your industry like all the other industries has to, from over zealous environmentalist like the beef industry has with PETA. Yet the protesters do not realize the ramifications of the proteins that derive from beef.

Who is defending our industry, and how can they do better?

Who will defend. Well first get off you government subsidised a$$, and stop thinking that someone else should do your work and defend it yourself (as an industry) and that usually comes from your industry itself.

phoenix911

He has a point. Your example being a good example of an industry that has a huge support base amongst government agencies and private organizations founded to foster consumer favoritism towards the product. Think things like USDA, California Milk Advisory Board, California Department of Food and Agriculture, Cattlemen's Associations, nearly every State Beef Industry Advisory Council, etc.. All of these promote beef and beef products, and spend a huge amount of money doing so (both government funds and private). The USDA alone spends a whloe lot of our tax money promoting these industries and products. So i guess it is a good question as i can not identify any real government agency, let alone multiple State and Federal Agencies that spend huge amounts of money promoting plastics. Oranges would be another good example of our tax dollars going to large expensive advertising campaigns. It is a good example of needing to seed a little lobbying money around Washington to get a huge financial windfall and free public awareness and promotions.

Makes a point? ..............sounds more like a government dependant.

California Milk Advisory Board, California Department of Food and Agriculture, Cattlemen's Associations, nearly every State Beef Industry Advisory Council, etc..like to add WMMB, Happy Cows...

All of those are check-offs from the Farmers' (Farmers when they sell thier product a small percetnage is checked off from thier checks to fund these)

As far as USDA, they are a government agency that counterdicts themselves. As I stated before, Don't depend on them. Defend your own industry, Its more effective.

Back in the 80's the price of butter drop, and the farmers were told to limit production.....even thou increases were limited the increases started to level off....except California.

Anyways, the price of butter started to increase for the farmers and then what happened, the government opened doors to New Zealand exports of butter because of the strounger price supports. It was more complicated than that, because it was a dimplomatic package wrap up in foreign policy with other items. i.e. words they would use advantages gain for foriegn policy.

Don't count on the government, They tend to subsidize farmers that should not be farming or corporate farms who are in it due to the government programs.

One more thing thats interesting, (2) years ago, milk farmers were getting for milk was $20.00 a cwt, (+ $20.00 per hundred pounds of milk) very good price.....too good maybe.

earlier this year farmers in Wisconsin were getting about $9.00-$10.00 cwt. That was the price we were getting back in the mid nineties and late 70's.

Tell the UAW.....would you except to get paid the same price you were back in the 70's so you can save your industry........no don't waste your breath.

phoenix911

I am not sure that government subsidized agriculture was the topic, but rather an example of government subsized advertisement of a specific industry. Yes dairymen and ranchers pay for portions of the advertisement, and the tax payers also pay large portions for "industry awareness" campaigns, etc.. too some degree it is like the government fears the society will fail if the low paying agricultural laborer jobs decline. The government does the same kind of subsidized advertisement for the US auto industry, and yes a lot of that is due to legislators fear of the UAW lobby. This is why i believe all donations to campaigns should be restricted to donations from specific persons and not LLCs, corporations, unions, and various non-material entities, and the maximum donations should be limited to persons living within the district for more than 1 year and no more than 10% of their average annual taxable income for the last 4 years (this has the added benefit of making very wealthy people report their incomes more fully if they want to make donations). No more lobbyists, no more high donations from people who write off all their income, no more donations from entities that have no direct connection to the public. I bet representatives would be more knowledgeable about the people they represent.

Hi,

In one short sentence.............

'Plastic' has such a bad rap because from the general publics observations, it is a very short life substance. The way it is used for the most part if to protect and dispose. So is has that rap as 'rubbish'.

When 'plastic' started to be used in cars and such it was the wrong sort and broke easily. It is not like that now but, there are thousands of toys and cheap items which are made entirely of plastic as there life is counted in months rather than years. Hell, you should know this if you are in the Industry!

bb

Right on babybear! ("When 'plastic' started to be used in cars and such it was the wrong sort and broke easily.")

It breaks because most engineers and designers don't know how to design with the stuff. They've been spoiled by the properties of metals and cannot understand that plastics have a greater range of limitations. And most of them are too dead-assed lazy to go into the resin manufacturer's instructions on how to design a snap fit, etc.

Then there is the manufacturing side. It is pretty hard though not impossible to screw up the basic properties of metals when you fabricate them. Even the scrap metal parts can be remelted and the original properties restored.

Not so with plastics. Time at high temperature breaks the polymer chains an kills the properties, especially toughness to resist cracks and breaking. Molding temperatures are right at the edge that way. When you raise molding temperatures 10 or 20 degrees so that you get better production rates you hurt the material. Ditto when you regrind and reuse previously molded scrap like gates an runners that have already had one high temperature cycle.

There is no easy way to measure that property loss in a finished plastic part. It looks great and works great until sometime later it falls apart in routine use. Every type of plastic bag clip that has ever been through our kitchen over 45 years has eventually broken. The expensive ones eventually break too. I finally found some pricey stainless steel clips made by Good Grips a couple of years ago. But now they've been "new and improved" into an all plastic (except for the spring) product and the old stainless ones are no longer available. .....sigh.......

Ed Weldon

Hello Ed,

Yes I fully understand your post.

I suppose the only way of being sure of the properties and strengths of any plastics, no matter what the end use, is to start with petroleum-based stuff only, with no ground up and other nasties involved?

And yes I think it is sad as well that so many good products are taken off the shelves, to be replaced with "new and improved' plastic models. What a lot of people do not seem to know or care?.............Is that any plastic which is getting zapped by solar rays with fall apart. Good quality plastic, like metal is not so likely to, as it is more carefully made. I am talking of the real expensive stuff like racing car bodies are made from carbon fibre. But in saying that, where does the definition of plastics begin and end? I have some plastic handled knives which are about 100 years old and still going strong. It depends on whether most people would call "bakerlite' plastic. But it is none the less.

Hey, take care my friend............

bb

Bakelite is an old brand name for reinforced phenolic thermosetting plastic that's been around almost 100years. The resin is reinforced with wood flour or other mineral fillers or paper or cloth in a laminated form. It was normally compression molded with heat to form things like automotive distributor caps, rotors and parts of electrical hardware where it's combination or strength, heat resistance (over 100C) and insulating properties are needed.

In the 1930's there was even a consumer fad over molded phenolic costume jewelry produced in bright shiny colors, which as one might suspect are collectors items today.

Phenolic use diminished in the 1950's as new engineering thermoplastics were developed; but it is still very useful for electrical hardware and is reasonably available in cloth reinforced sheets up to an inch thick.

Fiberglass sheet (like G10) is much more popular for things like circuit boards. But if you are planning to do any serious machining on the stuff such as making prototypes you need carbide tools.

OYOH the phenolic laminated sheets are a machinist's dream. It's especially handy to me for making little custom terminal blocks with brass screws and nuts for my model trains.

One thing about the mineral filled phenolic compression molded parts is that they are somewhat brittle compared with newer thermoplastics as anyone who has experienced a broken distributor cap or rotor on an older vehicle knows.

Bakelite in its several forms was good stuff well suited to most of ts applications. But it could be done wrong also. Some of us old time flathead Ford V-8 guys may remember the Harmon Collins Dual Coil distributors. They had a special tan colored plastic rotor and secondary distributor cap which after about 15-20 years would start to simply crumble into dust. An of course this was after they quit making parts for them. The Mallory distributor parts extensively used on Fords never had that problem. I guess their folks knew the right recipe for the resin.

Ed Weldon

You gotta love those old clunky Bakelite switches, i remember at school we uses this stuff to make things, a very nauseous smell when cutting and drilling in it

One way to avoid the environmental damage is to change back to plastics from hemp. Just like Henry Ford used.

(I emphasized 'change back' to drive the point that hemp plastics were quite common but have been discontinued due to "drug" policies ............. I will save my rant ........)

the hemp used for rope, fabric and such is not the same as marijuana

I know - that would be part of my rant that I have held back on

As others have said, plastics have a bad reputation because they are made too thin, or without the reinforcing parts they need. Who here hasn't had a self-tapping screw strip out of something. And almost any kind if left out in the sun will deteriorate rapidly. There are some good flexible plastics today, but they still have to have good designs. Forty years ago there was only Bakelite and maybe a couple more. I still have a tube tester that I made in a Bakelite case. It is thick, so never broke, but was very hard to work with. I made a large hole in one side with a propane torch (very ugly). Apparently I survived the noxious fumes. Today I have hole saws. Oh -- the good ole days!

It is a complex issue. Some commodity plastics sell for $.60 per pound, and some high strength, implantable grades sell for over $1400 per pound, and yet all are labeled "plastic." When new plastic grades first came out, many designers who were familiar with sheet metal and machined steel did not know how to design for them. They designed what would work fine for metals, but fail prematurely in plastics. Even now, many designers still do not know how to design for plastics, and I include some that work for plastics processors. The plastics design guides are available to anyone with an internet connection, yet the basic principles of uniform wall thicknesses, radii on inside corners, gradual transitions from thick to thin walls, ribs at 2/3 main wall, etc., are routinely ignored. Until more plastic parts are designed correctly and made with the right plastic materials, the plastics industry will continue to receive bad publicity.