Short Run SPC with Tool Wear

M

MSAFAI

#1
Hi everybody,

Here is a case in SPC, that I try to describe below:

1- It is a process using a perishable tool with high Cpk (2 or more),

2- There is tool wear, that causes the part diameter to gradually increase (indiacted by a slow trend on the X-bar chart),

3- Change of part diameter cannot be helped by readjusting the machine/tool. The only way is to change the tool with a new one.

4- The production is typically a "short-run" production. Completion of each order takes one to maximum 3 days.

5- After completion of the first order the tool is NOT changed, but the production goes on using the same tool for another product having the same diameter, but maybe different length, until USL (upper tolerance) is reached.

Any idea about what kind of Control Chart to use in such a situation?

I thought maybe a Nominal Chart would be suitable?

Thanks
MSAFAI
 
Elsmar Forum Sponsor
R

Rick Goodson

#2
MSAFAI,

The Nominal chart is appropriate for tool wear, however there are a number of cautions and requirements before you apply the chart. There is certainly considerable debate on what is a 'Save Process Average' which is a necessary part of a nominal tool wear chart. I would recommend reading Don Wheeler's and Davis Bothe's material on SHort Run SPC before applying the concepts.

Hope this helps.

Rick
 
M

MSAFAI

#3
Dear Rick,

Thank you very much for the comment. I'll try to find the material you mentioned.

MSAFAI
 
Thread starter Similar threads Forum Replies Date
P SPC Short Run Advice of a Stamping Process Statistical Analysis Tools, Techniques and SPC 3
D IMR (Individuals and Moving Range) Chart for Short-Run SPC - How much data to include Statistical Analysis Tools, Techniques and SPC 1
R What is a "DNOM Chart" in reference to Short Run SPC? Statistical Analysis Tools, Techniques and SPC 2
P Analysis of the figures from Dr Wheeler's 'Short Run SPC' Using Minitab Software 3
S Book for SPC Short Run - Recommendations Book, Video, Blog and Web Site Reviews and Recommendations 12
oldqamanager Short Run SPC Chart Template needed Document Control Systems, Procedures, Forms and Templates 5
E How to Effectively Apply Short Run SPC Statistical Analysis Tools, Techniques and SPC 33
S Short run SPC Seminars? Statistical Analysis Tools, Techniques and SPC 1
M Standardized P Chart for Short Run Production Statistical Analysis Tools, Techniques and SPC 13
B How to Demonstrate Stability and Repeatability in very Short Run Process AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 10
dsalcido Short Run Cpk and Minitab Capability, Accuracy and Stability - Processes, Machines, etc. 7
N Which is more appropriate Regular or Short Run control charting? Statistical Analysis Tools, Techniques and SPC 8
P Short Run Charts - Sample size N=1 Statistical Analysis Tools, Techniques and SPC 2
K Short run Z-bar & W charts - Can anyone tell me the formula used? Statistical Analysis Tools, Techniques and SPC 9
M Multivariable Control Chart - Target, Short Run, Group charts, T2, etc. Statistical Analysis Tools, Techniques and SPC 10
A Short Run Capability - Batch quantity is 15,000 to 20,000 Statistical Analysis Tools, Techniques and SPC 5
T Short Run - Low Volume Cpk Calculation Capability, Accuracy and Stability - Processes, Machines, etc. 10
T PPAPs for job shops that produce short run assemblies (i.e 100 to 10,000 units) APQP and PPAP 9
L Short Run Mfg Seeking QS9000 Certification QS-9000 - American Automotive Manufacturers Standard 2
S Precontrol and Process Capability - CNC Lathes that run small batches - Short Runs Statistical Analysis Tools, Techniques and SPC 12
Ajit Basrur Definitions - Short-term and Brief exposure Occupational Health & Safety Management Standards 2
supadrai My short yet eventful stint as a regulatory affairs lawyer dude is coming to an end! Career and Occupation Discussions 1
G Uncertainty of staging a short line scale standard on longer measuring machine? Measurement Uncertainty (MU) 4
A How to systemically improve product quality in short-term and long-term basis? Preventive Action and Continuous Improvement 1
B Short term vs Long term Capability - We ship millions of parts in a year Capability, Accuracy and Stability - Processes, Machines, etc. 7
A Short Term vs. Long Term SPC Study - Where is Cp and Cpk Defined Statistical Analysis Tools, Techniques and SPC 8
R Height gauge to measure short hard to access heights General Measurement Device and Calibration Topics 3
D Balancing between Strategic Objectives & Short Term Priorities Quality Manager and Management Related Issues 2
E Short Case Studies - Major/Minor Nonconformance, Observation or OK? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 9
kedarg6500 Sample Size for Short Term & Long Term Process Capability Capability, Accuracy and Stability - Processes, Machines, etc. 2
B Quality-related short term course in Perth Australia Coffee Break and Water Cooler Discussions 5
W Supply Voltage Condition for Transformer O/L and S/C (open & short circuit) testing IEC 60601 - Medical Electrical Equipment Safety Standards Series 4
E Expiration Date on Label for different Countries (Short Shelf Life Product) ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 5
Fender1 How to comply with ISO 9001 and provide quick/short lead-time orders? ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 13
P Understanding IEC 60601-1:2005, Clause 8.1 b) - Short Circuiting Double Insulation IEC 60601 - Medical Electrical Equipment Safety Standards Series 13
H Looking for short videos that cover what ISO 9001 is Training - Internal, External, Online and Distance Learning 1
R Are multi-faults needed? Effects of a Short Circuit IEC 60601 - Medical Electrical Equipment Safety Standards Series 7
R Should the fault tests pass if temperature goes high in short time? IEC 60601 - Medical Electrical Equipment Safety Standards Series 15
S Aspect vs. Impact and Hazard vs. Risk - Short/clear explanation & example Miscellaneous Environmental Standards and EMS Related Discussions 11
S Pp/Ppk & Cp/Cpk - Which is appropriate for Long/Short Term Study? Statistical Analysis Tools, Techniques and SPC 20
D Short Quality Cases for my Quality Workshop so I can make a Case Study Quality Tools, Improvement and Analysis 10
E Error Proofing to prevent Length Short - CNC Turning Process Manufacturing and Related Processes 4
Sidney Vianna Short notice audits - Have you been through or triggered one? Registrars and Notified Bodies 4
R Short-term vs. Long-term Variation Six Sigma 5
J Short Term and Long Term Quality Objectives AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 20
M Gage R&R Short Study vs. Long Study vs. Other Studies Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 25
A Injection Mold 100% Visual Inspection - Short Shots and Debris not being found Inspection, Prints (Drawings), Testing, Sampling and Related Topics 22
A Normal Deviation - short cut/method to calculate sigma Statistical Analysis Tools, Techniques and SPC 2
Chennaiite Interpretation of Short term vs. Long term Capability Studies Statistical Analysis Tools, Techniques and SPC 3
M Any Bridge Courses or short term courses available which helps the Career Training - Internal, External, Online and Distance Learning 3

Similar threads

Top Bottom