SPC on the shop floor - We are a job shop

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CMfgT

I have been collecting SPC historical data for about 6 months on our customers “key features”. We are a job shop, so we have many setups, but as long as they run the parts on the mean many parts are repeatable and stable. From the historical data, I can set control limits, but I am not sure what to do to keep the operators between the limits. What do you guys/gals do? Do you have a form and make the operators manually graph the data. That’s what I am leaning towards, but I would have to make different graphs. Does anyone have a simple form or solution to this? I don’t want to just collect numbers anymore, I want the operators to be aware of what is going on visually. Currently we just collect SPC numbers so they are available if our customers ask, and I run control charts and capability on minitab to verify we have a quality products, but I am missing the Process Control of SPC.

Thanks
 
A

andygr

Re: SPC on the shop floor.

The reason your customers are asking for SPC on Keys is that they want you to actualy use the tool. Granted in some cases they put it in the contract because it is "the thing to do" but since the requirement is there if your customer askes to see the data that you have you will not be able to show that there was proper action taken on the values that occured outside the limits and they will call you to task on that as quickly as not doing any SPC.
Set the tool up for the operators-make it easy- and then spend some time with them so that they know how the tool works and can see a benifit to their job and pride in making good parts. If your data shows cpk extreemly high talk to you customer about droping the feature from spc as there is little value in the tracking. Pick a feature that will have value.
:2cents:
 

Bev D

Heretical Statistician
Leader
Super Moderator
Re: SPC on the shop floor.

first - there are no shortcuts to "doing SPC". each process/product/feature will require a seperate chart. And if you can create teh same feature on different machines you may need different charts for different machines.

I always start slow - pick a few high impact (volume, revenue, critical to function) features to start. personally monitor the charts every day or several tiems a day if needed.

Hand charts are a great way to start particularly in a job shop and/or if measurements are manually taken without electronic download. The operators will have a closer relationship to the data if they are plotting the dots.

You will need a basic reaction plan to start. I usually document this in a flow chart (most people don't like to read paragraphs). First step is typically to check the graph - was the dot properly calculated and plotted. Next is the measurement system, was it correctly measured - a mini R&R (you don't need math here) including a reference check to ensure that the gage or operator hasn't changed. Then based on the process the operator woudl check the obvious suspects based on a mean or range change...at some point the reaction plan calls for callign the supervisor or QC person or engineer...as you and the organization gain experience in investigating out of control conditions, you will be able to firm up the reaction plan.

Once you are confident move on to other features...
 

ScottK

Not out of the crisis
Leader
Super Moderator
Re: SPC on the shop floor.

I collect the data with SPC software that automatically does the charts.
When something is going out of control we ask the set up guys to make appropriate adjustments and show them the charts if they are in doubt.

At this time QC does the data collection and analysis but we are slowly educating the machine operators and set up guys with the goal of having the operators do their own data collection and chart interpretation.

It's not a fast process unless you hired operators with SPC experience, which is not my case.
Baby steps.
 
C

CMfgT

Re: SPC on the shop floor.

I collect the data with SPC software that automatically does the charts.


What software are you using? This is my concern, making a form for the operators to document the information or make a control chart on.
 

bobdoering

Stop X-bar/R Madness!!
Trusted Information Resource
Re: SPC on the shop floor.

For precision machining, I use paper chart or Excel spreadsheet, because I have not found any packages that do the correct charting for the uniform distribution. :cool:
 
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