Setting and adjusting the parameters of the solder paste printing machine is a key step to ensure printing quality and productivity. The following is a detailed introduction to the main process parameters of the solder paste printing machine settings and adjustment methods:

I. Printing speed

Definition: Printing speed determines the speed of movement of the solder paste in the printing process.

Setting range: Usually, the printing speed is set between 15 to 200mm / s, the specific value needs to be adjusted according to the size of the PCB, the density of the components and the viscosity of the solder paste and other factors.

Adjustment recommendations: faster printing speed can improve productivity, but may affect the printing quality, such as uneven distribution of solder paste; slower speed may improve printing quality, but will reduce productivity. Therefore, the need to find a balance according to the actual situation.

Second, the printing pressure (squeegee pressure)

Definition: Printing pressure refers to the squeegee pressure exerted on the solder paste in the printing process.

Setting range: Printing pressure is usually set in the range of 2 ~ 15kg / em (or between 20N ~ 60N, the specific unit may vary depending on the equipment), the specific value needs to be adjusted according to the viscosity of the solder paste and the hardness of the squeegee.

Adjustment Suggestion: Proper printing pressure ensures even distribution of solder paste and avoids residue or insufficiency. Too much pressure will lead to deformation of the front of the squeegee, affecting the quality of printing; too little pressure may lead to insufficient amount of solder paste.

Third, squeegee angle

Definition: Squeegee angle refers to the angle between the squeegee and the stencil.

Setting suggestions: generally should be set scraper and stencil angle of 45 ° ~ 60 ° or so, in order to balance the downward pressure and avoid the paste is squeezed to the bottom of the stencil. Scraper angle if greater than 80 °, the solder paste can only keep the original shape forward without rolling, at this time the vertical direction of the force is almost zero, solder paste will not be pressed into the stencil window.

Fourth, scraper width

Definition: Squeegee width refers to the width of the squeegee and PCB contact part.

Setting suggestions: scraper width should be matched with the length of the PCB (printing direction), the general width of the scraper for the length of the PCB plus 50mm or so, and to ensure that the head of the scraper falls on the metal template. If the squeegee is too wide, it will increase unnecessary pressure and solder paste waste.

Fifth, the printing gap

Definition: Printing gap refers to the distance between the steel plate clamped and PCB.

Setting range: Printing gap is usually controlled between 0 ~ 0.07mm, the specific value needs to be adjusted according to the PCB and stencil flatness and paste viscosity. Part of the printing machine in the use of flexible metal templates also requires the PCB plane is slightly higher than the template plane.

Six, separation speed (mold release speed)

Definition: Separation speed is the instantaneous speed at which the steel plate leaves the PCB after solder paste printing.

Setting range: Separation speed is usually set between 0.3 ~ 3mm / s, the specific value needs to be adjusted according to the material, pitch and density and other factors. Precision printing machine in the steel plate leaves the solder paste graphics will have a small stay process to ensure that the acquisition of printed graphics.

Seven, cleaning mode and cleaning frequency

Cleaning mode: cleaning mode usually includes wet cleaning, dry cleaning or wet - vacuum suction - dry and other ways, the specific selection needs to be adjusted according to the type of stencil and printing status.

Cleaning Frequency: Cleaning frequency is usually set to print 8 to 10 pieces of PCB for a cleaning, but in the printing of small-pitch, high-density graphics, cleaning frequency needs to be increased accordingly. In addition, every 30 minutes is also recommended to manually scrub the bottom of the stencil with dust-free paper.

Eight, other parameters

Lighting Brightness: According to the type of solder paste and the color of the components on the circuit board, set the lighting brightness of the printing machine to ensure that the color of the solder paste after printing is consistent.

Auto-calibration parameters: According to the pad position on the circuit board and the specifications of the solder paste, set the auto-calibration parameters of the printing machine to ensure that the printing machine can automatically calibrate the printing position and angle.