QUALITY CONTROL ANALYSIS

STATISTICAL QUALITY CONTROL WHAT IS SQC??

SQC is a mathematical study used to investigate a manufacturing process to determine its precision and accuracy.

It is used to check and improve the quality control of a manufactured part.

Ensure products or services are designed and produced to meet or exceed customer requirements and expectations.

USING THE STATISTICAL PROCESSCONTROL ANALYZER

SPC EQUIPMENT

DIGITAL CALIPERPOWER SUPPLY

SPC PROCESSOR

CABLE

DIGITAL CALIPER PARTS

INSIDE MEASURING JAWS

OUTSIDE MEASURING JAWS

LOCK SCREW

MEASURING THUMB SCREW

DIGITAL WINDOW

DEPTH MEASURING

NEVER GONNA LET YOU DOWN

CABLE CONNECTED TO SPC ANALYZER

Cable tab lines up with slot in socket

NEVER GONNA RUN AROUND AND DESERT YOU

SPC ANALYZER BUTTONSClear limits

Clear entry

Feed paper tape

Enter data

Enter upper & lower tolerance limits

Statistical analysis of entered data

NEVER GONNA MAKE YOU CRY

ABBREVIATIONS FOR STATISTICAL DATA TERMS

USL - Upper statistical limit of tolerance LSL - Lower statistical limit of tolerance N - Number of samples taken or data points Max - Maximum value of largest sample Taken Min - Minimum value of smallest sample Taken R - Range of values taken

More Abbreviations X bar - Mean of all samples taken O n - STANDARD DEVIATION OF ENTIRE population of samples O n-1 - Standard deviation of a sample of entire population P - Percentage of defective samples (Parts out of specs) Cp - PROCESS CAPABILITY SHOWS precision of process Cpk - Process capability shows both accuracy & precision

SPC ANALYSIS STEPS USING TOLERANCES

Press (CL) key to clear limits Press (TOL LIM) key to set upper and

lower statistical limits of tolerance used Zero digital caliper Manually set caliper to upper statistical limit Press (data) key to set USL (will show on tape as (lmt) Manually set caliper to lower statistical limit Press (data) key to set LSL (will show on tape as (lmt)

The rest of the Steps

Press (TOL LIM) key to show tolerance limits on paper tape as (usl) and (lsl)

Now use the digital caliper to enter measurements of the sample and press the (data) key each time

Repeat above step at least 10 times to get 10 samples Press (stat) key to perform a statistical analysis of all the

samples entered Press (feed) key after printing stops to advance paper

SETTING UP SPC

Press (ON) key

Tape will show

*Print On*

Press clear limit (CL) then total limit (TOL) tape shows

*Limit Clear*

SETTING UP SPC

•Turn (on) caliper

•Slide jaws together

•Press zero key

SETTING UPPER TOLERANCE LIMIT

Manually set USL of .115 thousands on caliper then press DATA key. This will show on tape as (lmt)

SETTING LOWER TOLERANCE LIMIT

Manually set LSL of .105 thousands on caliper press data key. This will show on tape as (lmt)

CHECKING TOTAL LIMIT

*NEW LIMIT DATA* LSL 0.1050 USL 0.1150 TOTAL LIMIT .010

Now press total limit key the tape should read as shown below with a tolerance of .010 or USL-LSL

MEASURED SAMPLES OF A PART

Take 10 measurements of the part by pressing the data key after each measurement. This can be done in two different ways as shown.

Sample being measured in 10 spots

ANALYSIS OF DATA TAKEN

After all measurements are taken with the caliper and entered into the (SPC) press the (STAT) key for a full analysis of data

Data analysis is printed on paper tape

THE TAPE

LimitsTolerance

Readings

Statistical data

Histogram