Mahr Digimar 817 CLM Operating Instructions Manual - page 121
121
Mahr GmbH • Digimar 817 CLM
8.4.5
Selection criteria
Data selection can be activated by selecting the menu
„Selection criteria“ by histogram and control chart
In this example, 6 criterions are selected. Mr. Brown
inspects all parts between the 1.02.2007 and the
28.02.2007, from the 2nd shift. They were tested on a
coarse tooling machine, for the customer BB and the
quality standard is 4.
1. <-_______
2. Display histogram and statistics
3. Print out histogram and statistics
4. Histogram parameters
5. Selection criteria
1
+
0
2
ABC
3
DEF
6
MNO
5
JKL
4
GHI
7
PQRS
8
TUV
9
WXYZ
/ : , *
– Table function, skip to the next criteria
– Return to exit
8.5
Control charts
The quality control chart is used for the evaluation of
inspection data out of a sampling procedure; based on
this the inspection data of the sample, for example
workpiece sizes can be shown as a graph. Plotted on
the quality control chart are so called warning limits
and control limits; these could be used for example as
define workpiece tolerances.
When reaching the
warning limits it is important to
intervene at the earliest possible moment as well as to
increase the number of inspections and to search for
the process error.
– Edit selection criteria
When reaching the
control limits it is very important to
intervene as early as possible to prevent the
production of defective parts. When the progression to
faulty production has dropped, then it is possible to
observe ahead of time in the quality control chart and
thus preventing further defective parts being produced.
Therefore, there is more time to intervene in the
process and to prevent faulty production.
The quality control chart can be viewed as an indicator
for the process. With the evaluation of a quality control
chart it is essential to be able to differentiate between
coincidental and systematic influences. Coincidental
influences leads mean variation of the inspection data
Start : 01.02.2007
Stop:
28.02.2007
MACHINE
5
TESTING
OPERATOR
2
BROWN
SHIFT
2
S2
TOOL
2
ROUGH
CUSTOMER
2
BB
SAMPLE COMM
4
Q4
All parts
Parts n.: 1 - 9999