Why implementation of Scientific Molding fails for some companies??

[Suhas]

Hello All,
What in your opinion is the biggest reason for companies having issues with implementation of Scientific Molding? Please let me and the rest here know. It will be very insightful.
I recently wrote about this topicI wrote my thoughts here - http://fimmtech.com/index.php?id=6&subid=53
Thanks,
Suhas

[EBSMITH]

Most of the companies I have worked for have all the same reasons for SM failures, pillars not followed, even when they try to follow them, time is a huge factor for failure. The customer is expecting parts by a certain date, milestones slip thru out the project but the end timeline stays firm, the result is, the process development gets squeezed and shortened and pushed thru to meet a deadline. Many times I have seen what should have been called engineering samples get measured and data sent to the customer without even having good mold function, or no end of arm tooling completed yet so the parts are not even representative of what the production process will produce. Almost never does a mold come out, you do all the studies and then you modify the steel to fit the process. End result is smaller process windows.

[cavaliersw]

I have had success with scientific whenever i get a chance to use it. The obstacles i have encountered are regrind percentage, machine condition. in order to save a buck regrind is used at it's fullest. For instance we have a few jobs that run 99% to 100% regrind. Fat chances of scientific molding keeping a steady process. The screw and barrel wear also prohibits this. it a perfect world these would be controlled and maintained but again, fat chances. We have been getting new machines and the issue doesn't apply. I can set a process very quickly or a machine that has been maintained. Some of the older ones, i don't even try to set up since it will not flat line leaving the opportunity to dance on the controls. Instead i just have to standard mold it.
Scientific molding is very robust if the conditions are met first then everything will fall into place

[Josue]

some companys Never try to implement, Becasue
a)dont want to invest in training to understand scientific meaning
b)Time,,,,, every thing need to be Urgent, for "yesterday" , mold validations, mass productions, etc,,,
c) neglet maintenance activities, many machines with barrel/screw damaged,,,

[rickbatey]

I have had success with scientific whenever i get a chance to use it. The obstacles i have encountered are regrind percentage, machine condition. in order to save a buck regrind is used at it's fullest. For instance we have a few jobs that run 99% to 100% regrind. Fat chances of scientific molding keeping a steady process. The screw and barrel wear also prohibits this. it a perfect world these would be controlled and maintained but again, fat chances. We have been getting new machines and the issue doesn't apply. I can set a process very quickly or a machine that has been maintained. Some of the older ones, i don't even try to set up since it will not flat line leaving the opportunity to dance on the controls. Instead i just have to standard mold it.
Scientific molding is very robust if the conditions are met first then everything will fall into place
A good stable process will tolerate regrind and virgin ratio fluctuations with NO to only small adjustments.
When I see SM implementation fail, it's due to the Long in the Tooth pack resisting it, or a lack of understanding by management of its capabilities. You can't use it for every part! But it takes an experienced molder to know when he can, and can't mold a part with these techniques. I see more guys live and die by the SM sword because they've no idea how to mold any other way! My tarnished two cents. Rick.

[Suhas]

Good Points Guys! Thanks.
I live by these techniques but as Rick says - CANNOT be used on all the mold out there.
Just finished a project with a major captive molder on a 64 cavity mold, polyolefin, 8 seconds cycle, molding millions of parts a year. Tolerances are +/-0.002" (multiply the complexity by 64 cavities, 24 hours a day!) It us about a month or so but it is working GREAT. Robust and stable process - Cpks> 1.33. Like the energizer bunny ... keeps going and going and going ...
Regards,
Suhas

[Moldrite]

Here is a scenario I heard about at my local monthly SPE meeting.
Supervisors hear about the "scientific" way to mold and decide they want to make better product and a more consistent process allowing them more time to do other action items.
They go read some articles , download some software and try the 6-step process from start to end.

This was the first try.
Material 20 melt clarified pp. 24 cavity hot runner. 10.3sec cycle.
Viscosity test- went well. Plenty of data points. The speed that they chose had a small percentage drop. The next portion is a quote , "we used the speed that we thought to be correct and the dang machine blows right past the transfer" "we get consistent weight, but it's always past the transfer" My question was "did you slow it down to a point that the machine would maintain a specific shot size?" Answer "yep, but the speed we have to use is not even close to the flat portion of the curve, so we figured either the instructions are flawed, missing a step or are for a specific machine or material or whoever came up with how the values are calculated made a mistake, so after 3-4 hours downtime we gave up for the day"

Needless to say they never got over the "slamming it home and passing the transfer every time."

So, they gave up.

They continue to run 24 machines, 24-7, making millions of parts per month with no appreciable internal rejects and no externals. Or so they say.

[RycheMan27]

Many excellent points are made in the responses to this question. I wrote an article some time ago on the subject. Some readers may find this interesting. Follow this link to read it for yourself.http://www.ptonline.com/columns/top-10-reasons-why-molders-fail-at-implementing-scientific-molding