00198574-01_Process_Foundation_DEK_Micron_EN - 第52页

7 Product File and Machine Optimisation

7.3 Design a Paste Knead Strategy

Process Foundation DEK Micron-Series 12/2017 51

Exercise

Discuss the knead parameters with your instructor and complete the table below.

Parameter Description Comments

A careful inspection should be

made of the print quality on a

board that has been used for

kneading. Multiple print strokes

can increase the risk of

excessive print deposits or

bridging.

7 Product File and Machine Optimisation

7.4 Provide a Definition of all Advanced Product File and Machine Set up Parameters

52 Process Foundation DEK Micron-Series 12/2017

7.4 Provide a Definition of all Advanced Product File and

Machine Set up Parameters

The DEK software contains many programmable parameters. All of these serve a useful purpose,

but maybe not all at the same time or for the same application. For instance: some parameters are

only used for printing low viscosity materials such as ink; some are for adhesive printing; others for

solder paste. It is important that the person designing a new product file is aware of which

parameters are relevant to their particular application.

Exercise

Review all the parameters in the product file and machine set up menus then answer the following

questions.

Q1 Which parameter controls the speed that the squeegee moves upwards off the stencil at the

end of a print stroke?

………………………………………………………………………………………………

Q2 Under what circumstances would this parameter be adjusted?

………………………………………………………………………………………………

Q3 Which parameter enables the option to perform an automatic paste dispense whilst a screen

clean is being performed?

………………………………………………………………………………………………

Q4 List a minimum of four other product file or machine set up parameters that can be adjusted

to achieve the following:

1. Increase Machine Throughput

……………………………………………………………………………………………

2. Decrease Cost of Production

……………………………………………………………………………………………

3. Increase Percentage of Effective Printed Boards

……………………………………………………………………………………………

Notes:

………………………………………………………………………………………………………………

7 Product File and Machine Optimisation

7.5 Optimise Parameters to Produce Acceptable Quality Prints at Higher Throughputs

Process Foundation DEK Micron-Series 12/2017 53

7.5 Optimise Parameters to Produce Acceptable Quality

Prints at Higher Throughputs

Aim

To optimize the product file and machine set up parameters to be capable of printing twenty

consecutive boards at the stated throughput with zero print defects.

Required throughput: 300 boards/ hour

Step 1

Calculate the required cycle time for the stated throughput ………………..s

Hint: Calculate the cycle time assuming that there will be no under screen cleaning but be

aware that if cleaning becomes necessary it will significantly reduce throughput hence the

cycle time will need to be increased.

Step 2

Estimate the required separation speed ………………..mm/s

Estimate the required separation distance ………………..mm

Hint: Use 10mm/s and 2mm distance if you are unsure of the paste performance.

Step 3

Determine through experimentation what print speed will

achieve the desired cycle time

………………..mm/s

Hint: Cycle a batch of boards through the machine left to right with no squeegees fitted and print

pressure set to 0kg. Vary the print speed until the desired cycle time and throughput is

achieved.

Step 4

Record below any other product file or machine set up parameters that you had to change to

achieve the required cycle time.

Note: Speeding up the cycle time can lead to instability of the process so any changes should

be monitored closely.