# Measurement Service for Determining Positioning Accuracy on SMT Equipment

## Determination of Positioning Accuracy for Glue Dispenser

• Determination of positioning accuracy for glue dispenser
• Impartial and independent measurement analysis complying with DIN ISO 17025
• Diagnosing root causes of misplacements and deducting the offsets correction
• Validation of the offsets correction efficiency
• Improvement of the placement quality through fine-tunings the positioning accuracy
• Calculation of $$C_m$$ and $$C_{mk}$$ values based on defined specifications
• Declaration of conformity according to given specifications in consideration with measurement accuracy and given target values
• Detailed und meaningful test report

### Preparation from CeTaQ

• CAD-Datas to create the placement program with consideration of the properties of the analysed machine like :
• Number of dispensing nozzles
• Placing area
• Calibrated Glass board used with the CAD-Datas
• Mobile Measurement system CmController to perform the tests

### Preparation from Customer

• Validate and finalize the dispensing program from the specifications defined in the CAD-Datas.
• Guarantee a good state of the analysed machine through maintenance and eventually a calibration.
• Standard SMT glue for Dispenser. Usually, specific type of glue is not necessary and standard Process tools can be used. The most important is to get a good black shape of deposit where the light is not passing through.
• Table and access to AC power socket close to the dispenser machine to install the measurement system.
• Technical support to operate and program the equipment.

### Placing Glue Deposits 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. Finally the glue dots are dispensed on the boards as defined in the placement program. Eventually, adjustments of the dispensing parameters are necessary. The objective is to get well defined round and repeatable deposits.

### Measurement of the Glue 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.

### Analysis of the Results

The measured values are used to evaluate the positioning accuracy of the equipment. 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

Right after the analysis of the results, it is usually possible to optimize the accuracy of an equipment using correction offsets. In the simplest case, the advise could be for example to run a calibration using the tools provided by the manufacturer. Frequently, it's also possible to perform offsets correction directly into the machine software. Therefore, based on measured values, direct corrections can be made.

If mechanical causes are the reason for inaccurate placement, 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.

Finally, after applying the corrections, the effectiveness is verified with another measurement. According to result other measures followed from examination measurements arise from it if necessary. Depending on the results, other measurement will be done if necessary.

### Report Writing

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.

• Measurement system and dedicated glass boards are calibrated in conformity with DIN ISO 17025.
• The procedure is suitable for all type of SMT placement equipment.
• The required time for a complete evaluation depends on the type of equipment. As a rule it takes between 30 minutes and 5 hours. Typically, the study takes around 2 hours.