In spite of the high-tech of our shop floors you can still see pencil and paper data collection being used.
Data collection in the shop floor is a non-value-add operation which is still required to control the process.
This collection is often automatically done by the manufacturing equipment with no operator intervention.
Unfortunately, detecting aspect defects is often difficult to automate even with AOI (Automatic Optical Inspection).
When an operator is required to inspect we need a method to enter the results into the system.
Line incidents, change of critical process parameters, etc. also need to be reported.
The method still widely used in this 21st century is:
- The operator hand writes the defect data on a form
- Forms are collected at the end of the shift
- A clerk types the forms contents into the system at a later stage (next day or later)
- The engineer analyses the results and takes corrective actions
This reporting process creates a number of problems:
- It is time consuming for the operator
- It adds a non-value-add operation: transcribing the data
- The operator’s handwriting is not necessarily good (this criteria is not used for operator selection)
- Reporting errors may be introduced both by the operator and the clerk doing the transcription
- Some of these errors may be impossible to recover when they are detected on transcription
- Real time process control is impossible: the engineer detects a problem at least 24h after it happened.
- Maybe they have been producing bad product all this time.
The alternative to the pencil & paper data collection is, of course, directly reporting defects in a terminal the moment they happen.
You can provide terminals in the inspection and test stations to do that.
Sometimes it is difficult to provide individual terminals to all the operators who need to report. Sharing terminals and having to walk to the nearest terminal is time consuming so it may not be acceptable.
The reporting operation should not be time consuming and error prone. If we ask operators to type 12 digit numbers or time stamps the chances of error are very high.
So we need a reporting system which is both simple and error free.
Large number typing can be replaced by a bar code reader whenever possible. We can also use the data validation alternatives provided by Excel:
In this way the reporting errors may be detected the moment they are entered and corrected on the spot.
Pull down menus may be used for each field to avoid typing and insure all use the same wording.
The current time stamp can be automatically provided with a formula: =now()
Reporting on the cloud
Having a terminal for each operator who needs reporting may not be possible, in which case reporting on the cloud may be an alternative.
The data base can be created in a Google Drive spreadsheet:
Reporting may be done with any tablet or smart phone via WIFI
BYOD (Bring Your Own Device) alternative
Operators may have difficulties with readable hand writing or reporting in a terminal but they are normally experts in typing into their own smart phones. This existing skill can prove to be very useful for real-time on-line reporting.
The database may be in Internet or the company Intranet.
The smart phones used may be the operator’s own device or one supplied by the company.
It, obviously, requires appropriate firewalls to avoid entering virus.
Even a smart phone with no telephone line may be used to access via WIFI (an old out-of-use smart phone might do the job).
To avoid corrupting the database each workplace may have a dedicated input worksheet in the cloud and then data is automatically transferred to a central worksheet. Operators need write access to their input worksheet and only read access to the central worksheet and reports.
Real-time feedback to the workplace
Real-time data collection enables real-time feedback to the operators in order to take corrective actions while it is still possible.
This Andon display provides real-time feedback:
- PTH component insertion DPMO (red means above 1500 target)
- PTH component solder DPMO (green: below 190 target)
- Processed cards/hour.
SPC (Statistical Process Control) Charts is another alternative to provide feedback to the operators in real-time.
When this feedback is in real-time it is possible to relate changes in the output to what just happened in the line: change in process parameters, line incidents, etc.
This makes it possible to get to the root cause of problems and often solve them on the spot.
Pencil and paper data collection makes it impossible to provide real-time feedback to the operators: all we have is after-the-fact compound data. In this case it will be difficult to find the root cause of the problem and therefore the problem will often remain unresolved. All we can do in this situation is guess what happened and try to find a justification for management.
With pencil and paper data is often missing and there are errors which often can't be recovered.
Data may be easily entered into a spreadsheet in the cloud, via WIFI, using an existing smartphone.