What type of SQC or SPC Techniques can be implemented in Machine Shops

[viren]

Hi

I recently joined the quality control department and i found that there are no sqc or spc techniques are getting implemented so i wanted to seek help from friends that what type of sqc or spc techniques can be implemented for small machine shops.

i have some basic knowledge about statistics i request you friends to give some elaborate idea to implements the sqc/spc successfully
thanks

 

[justncredible]

Re: What type of sqc or spc techniques can be implemented for machine shops

First figure out what you want to monitor, then you have to make sure the device you use is capible of measureing the item. So first step is to plan what studies will help, such as common returns due to wrong size diameter. Then you figure out the best gage to measure that item, then you will do a MSA on the gage. Then you may start to gather the spc.

 

[ScottK]

Re: What type of sqc or spc techniques can be implemented for machine shops

Hello viren...

I think the first thing we need to look at is what kind of production do you do?
Are the long runs with lots of parts being produced, or short runs with a few parts?
Is it automated equipment or manual operations?

Example - my company is a "machine" shop and we use automatic screw machines. We have some parts that will run for weeks, making thousands of pieces and we have shorter runs that may be done in 8 hours.
Right now we focus on the longer runs and will be looking to short run SPC at a future time. They use somewhat different techniques.

 

[bobdoering]

I highly recommend reading through the following link:

https://elsmar.com/Forums/showthread.php?p=187696#post187696

It may save you a lot of grief from improperly implementing SPC. For any precision machining, do NOT use X-bar-R charts. Use the X hi/lo-R chart described in the link. You will avoid loads of grief. Do not buy SPC software - most is wrong for precision machining.

 

[viren]

Thanks for your replies friends,

Yes, the jobs what we do are almost all are high precision jobs, i will follow your suggestions. The production is very small the highest will be around 20 and the lowest will be around 1. This is the real problem for me to do any thing like to compare the results or to do any thing, thats the reason why i am here for your help.The scrap rate is nearly zero as we can not afford to scrap any material, the cost of material is so high. Even the returns and reworks also literally zero, being a small shop we take utmost care to avoid anything unwanted as we can not afford any mistake.

I hope i will get help.
Thanks again
viren

 

[bobdoering]

For those just coming across this forum topic, a more complete explanation of the SPC technique for precision machining can be found at Statistical process control for precision machining

 

[viren]

Thank you sir

 

[M.SHANMUGHAM]

hi

i recently joined the quality control department and i found that there are no sqc or spc techniques are getting implemented so i wanted to seek help from friends that what type of sqc or spc techniques can be implemented for small machine shops.

I have some basic knowledge about statistics i request you friends to give some elaborate idea to implements the sqc/spc successfully
thanks

hai,

for continuous production ,you can use run charts to control the critical parameters

 

[bobdoering]

for continuous production ,you can use run charts to control the critical parameters

Run charts are not quite as adequate as the X hi/lo-R charts in the links described above. The X hi/lo-R charts provide much more accurate feedback on when to adjust the process, tool wear rate, and when even when to change tools - if you are doing precision machining and controlling it correctly.