Material consumption

[fabrice2410]

Hello

i m new in the world of injection molding. i m the production manager of a plant where we have 49 injection machine. I don t have a lot of experience in injection.

we have an issue with our material consumption i try to solve. we are consuming 10% more material than it s supposed to be and i need to solve this problem because it costs a lot of money to the company. we have the big picture, but we dont know from where it s coming from

the only control we have today is to weight the part at the beginning of each shift and check discrepancy. but even with this, i still have problem.

i was thinking about a device that could meseasure the real consumption of the machine but it seems this kind of device does not exist. am i right ? i would then compare current production versus theoritical, then deduct which item is giving the issues

can anyone give me best practice to put the consumption of material under control ?

thanks

Fabrice

[MTUHusky]

Hey Fabrice,

Do you weigh and document your purge? I would start with the purge, if the machines go down and the Foreman purge the machine before they restart it (like they should be doing) then that could be where some of the material is going. I am not sure why you weigh your parts unless you are intentionally running without gate seal. If you have proper gate seal, your parts should weigh the same from shot to shot. If your parts are changing in weight from shot to shot then you don't have gate seal. Now the runner may not have gate seal and doesn't need it so there could be extra material packed into the runner, but I doubt 10%.

Also, what is your scrap rate? Are you properly documenting all of your scrap? How is your material handling? Are you material handlers documenting any and all spills and unused material (material left in the hopper after the run).

There is a lot of places material can sneak off too. Documenting everything is your best bet.

- Husky -

[iautry1973]

Husky is on the right track. Analyze the whole picture. Scrap and purge often get overlooked or poorly recorded. Sometimes employees feel they will get in trouble for accurately recording scrap because they think they will be blamed for the loss of product. Reassuring them it is a tool to help improve the scrap rather than something to yell at them for helps. I worked for a company that would weigh all the material before a run. They allotted enough material for the run with a little bit of extra. At the end of the run they would weigh it and make sure to explain losses. If you ran out of material and needed more the supervisor had to request more material and figure out why they needed it. made it something that was dealt with right away rather than at the end of the month when inventory was done.

There is a few weigh scale blenders that have the ability to record how much material they use. Maquire and Conair I think have them, but there might be others I haven't seen.

[chrisprocess]

Maybe need to update the BOM

[chrisprocess]

If all new and existing project BOM information is correct, then find out if the scrap is during start-up or from quality issues.
If there's quality issues then work on minimizing those issues if possible.

Wouldn't be a bad idea to get a team together for a Kaizen event and understand material flow through your plant.

[fabrice2410]

thanks for your advices

[Suhas]

Hi Fabrice2410,

Two more things to take into consideration:
1. I once had a company weighing parts all the parts in lbs. Even 20 gms was converted to lbs that threw out the last few digits and they lost material. I hope that is not the case with you.
2. If you are using filled material, then there is always a variation in the %filler.

Regards,
Suhas

[JayDub]

Back when I worked with large parts and expensive materials, resin use was tracked by work order. Each job (part number) had a part weight, start-up & shut down allowance, plus an assigned scrap rate based on job history. So a work order for a thousand pieces of a one-pound part with a 10% scrap rate, 10 lbs of purge for start-up and 5 lbs left in the barrel at shut down would be assigned 1000 + 100 + 10 + 5 = 1115 lbs of resin. If the job used more resin, that would be issued separately and logged as a material variance. Material variance costs were tracked on a variance report for management review.

Here’s the critical point: the variance report needs to be used as a tool for investigation and improvement. If you just use it as a stick to beat people over the head with, they will find ways to game the system, which will cost the company more money in the long run. In our case – I kid you not – one point two million dollars.

[iautry1973]

JayDub, been there got the tshirt LOL. Nothing more fun then trying to figure out who stole half a Gaylord of material to make up for their shortfall. Worked at a place with a system like that. It was used as a club and the warehouse manager and molding could not get along....so reallocation of other jobs was done to catch up short jobs. Always led to someone (me usually) having to go to the warehouse manager and explain that I have no clue (I had an idea but no proof) who did what with the material. Usually ended with a "if you don't want to give us the material just let the GM know why the parts didn't ship"