Production Standards - Machines

[PennStateIE]

I'm getting ready to set production standards for some machines and was looking for a little reminder.

I've done the time study on the machine and let's say when running it can produce 100 parts per minute.

Do I leave allowances (other than known breaks when the machine will not be running)? If so, what's typical?

Also, I can time the machine running at 100 parts per minute, but I'm told that when the machine is run slower (for example at 85 parts per minute) there is less downtime. Any ideas on how to calculate this or capture this information?

 

[PSE]

You should consider how much operator intervention is involved with part production. A big one is typically setup to do a run (assuming the machine is not dedicated to that part alone), this may include first part inspection to verify the setup as well. Does the operator do in process measurement of parts requiring temporary shutdown? You should leave some allowance for tool changes in the event of breakage etc.

Your process yield should be something to look at in terms of downtime. You indicate that there is less downtime at 85ppm vs 100ppm. Is this due to machine or tool wear or does the rate affect the quality yield? Does the 15% drop in throughput increase the quality yield by over 15% and/or reduce the MTBF or required preventative maintenance by over 15%? Check and see if there is some value ($ savings) there.

Regards,

 

[griffengm]

PSIE,
You might want to get a copy of Maynard's IE Handbook so you have a more citable source than the web. If you ever need to defend a practice you will be glad you had it.
The fact that the set up of the machine influences the output so much argues for a defined setup process for this machine. If you can change the rate by 15% in the setup it will be difficult to hold an operator to a production standard within 25-30%.
Who does maintenance and set-ups for this machine? Who deals with problems such as misfeeds and jambs? Talk to them and maybe have them log their service time over several jobs. Keep in mind that various stakeholders may have their own reasons for wanting the setting one way or the other but the best usually occurs somewhere in the middle.
Good luck!

Griffy

 

[PennStateIE]

Thanks. I did leave time already for changeovers, breaks, etc.

I was just curious what a typical number for allowances would be?

I'm also curious if anyone has some rule of thumbs for downtime. This s a packaging line and we experience pretty heavy downtime (over 30% monthly)....I'm dowing Pareto Analysis, talking to the operators, talking to the mechanics, each one blame the other, it's interesting to say the least!

 

[griffengm]

Just to make certain of the semantics here, does "downtime" include setup/changeover time or exclude it? Under what term do you place maintenance or service?
Thirty percent including all of the above might be okay under some circumstances but at the very least argues for implementing Quick Die Change methodology. Six mandays per month of downtime if the term excludes changeover is way out of line.
The fact that various groups are finger pointing would seem to say that someone in management has bought into their arguments in the past and they hope it works again.

Griffy

 

[BML]

If the downtime is true "machine down due to broken tool" time, then the concept of running slower to reduce downtime is absolutely valid. I've seen case studies in the garment industry that support this. What you may want to do is a quick DOE study with feed/speed as your input and downtime as the output. You should then be able to show how part cost goes down the faster the machine runs, but maintenance cost goes up. Then find the setting that minimizes total cost.

Hope this helps!

 

[PennStateIE]

BML,
Thanks. Yes, downtime is due a broken tool. The problem I face is that operations says the tool was broken and maintenance says the tool broke because operations didn't have the settings right....it's a mess.

Thanks for your help.