Printing on the Glass Board
The equipment to analyse is prepared with the help of technical support. The dispensing program loaded and the glue supplied.
Then, the glass board is loaded into the placement equipment.
The machine validates the position of the glass board with the help of fiducial marks.
Afterwards the first print takes place.
Eventually, adjustments of the printing parameters are necessary.
The objective is to get well defined round and repeatable deposits.
Measurement of the Deposits
Once the glass board is populated with glue deposits, it is inserted in the CmController and the x,y positioning accuracy of the glue deposits will be measured.
The measured position is compared with the nominal position.
These datas are the basis needed for further analysis.
Validation of the initial State of the Equipment
Both steps, printings and measuring are many times repeated.
Aim is to judged the final state of the equipment during all prints and also for each print directions.
In addition, numerical and graphical tools are available in the analysis software CmCStat.
Beside the statement does not limit itself to a simple judgement like specifications reached or failed.
Therefore, many detailed information are displayed to help in failure root cause analysis.
For example, dependencies between offsets and nozzles or angles of placement are identified.
This knowledge gives explanation on how the accuracy of the equipment can be improved.
Use of the Results to Optimize the Accuracy
Based on the final state, some possible offsets corrections are determined.
This are generally offsets depending on each printing directions for example.
Most of the times, those measured offsets corrections are adjustable in the machine software or directly in the machine.
It allows, based on the measured datas to apply these corrections immediatly.
If mechanical causes are the reason for inaccurate printing, the measuring results can be used to identify the problem by ordering the sequence with groups.
It facilitates the failure diagnosis for the maintenance service.
Validation of the final State
When all corrections are made, a certain number of printing is done, as a rule 25 in total, without any changes in the equipment.
These will determined the final state.
The repeatability is calculated.
The influences of inaccurate printed dots (bad shapes) on the result are thereby eliminated.
Based on the reached final condition, a test report is written at the end of the evaluation.
This is written usually in our office after customer visit.
Beside the detailed description of the final results, it contains the history of the necessary steps to reach the final condition.