From the beginning of the industrial revolution in the mid-eighteenth century, humans first tasted the sweetness of machines instead of handcraft. For the next two centuries, humans have been seeking more effective machines instead of manual methods. With the development and advancement of technology, better and more efficient methods are constantly being created. Today, automated production has become more and more popular. At the same time, in the rapid development of automation, the SMT chip soldering manufacturing industry is constantly developing and producing simpler and more automated patch soldering inspection equipment.

 

PCB LED Pick & Place Machine is a system engineering, it is a comprehensive technology involving a wide range of aspects, in the selection of printed boards, design specifications, production processes, placement methods, equipment process selection, SMT placement machine program fabrication, etc. Seriously consider and study. Among them, whether the equipment selection configuration and production process are consistent is a measure of an SMT production line and management level.

 

A rare electronic factory SMT placement machine the most comprehensive key placement technology control strategy! Hope to help everyone!

Placement technology control strategy

First, the concept of component patch

Second, the component patch control point

Third, component patch - equipment maintenance and maintenance

Fourth, component patch - patch quality monitoring

V. Component SMD——Identification and Analysis of Feature Defects

 

First, the concept of component patch

When the solder paste is printed, the next step is to place the SMT-type parts on the surface of the PCB and then form an electrical connection between the part and the PCB via reflow soldering.

The SMT parts are loaded into the special feeder (FEEDER) of the placement machine, and the parts are sucked through the nozzle of the placement machine (NOZZLE), and the parts are accurately attached to the PCB through the pre-completed patch program control. Above the pad, complete the replacement of the SMT part.

 

Mounter is attached to IC chip

 

Second, the key control points of component patch:

The component patch is generally a post-printing process of solder paste. The purpose is to accurately place various patch components on the printed circuit board to ensure that there will be no wrong materials or missing parts after the furnace is finished. A series of quality problems such as polarity reversal, positional offset, component damage, etc. The patching process is the core part of SMT. The process capability of the placement machine and the quality control of the specification are important factors to ensure the quality of the final output of PCBA.

 

In order to ensure quality, in addition to the correct machine parameter settings, you should also pay special attention to and pay attention to the following aspects:

· Equipment maintenance and maintenance (including Nozzle, Feeder, etc.)

·SMD quality monitoring

·Identification and analysis of feature defects

 

Third, component patch - equipment maintenance and maintenance (including Nozzle, Feeder)

·Nozzle (every month)

Since the nozzle is operated by vacuum, some external objects are sucked in. When the inhaled dust, glue, and solder paste harden to form a block, the nozzle will be blocked. If the foreign matter is not cleaned up in time, the performance of poor suction and placement will be greatly reduced. (The components are misaligned and have a corner; the missing parts are irregular, generally large and heavy components are prone to occur; the components are not absorbed; the components are prone to errors due to image.)

 

If a blocked nozzle causes a poor suction, insert it with a small drill as shown below and turn it left and right to remove foreign matter.

 

If there is dust or other small foreign matter on the reflective paper of the nozzle, the brightness of the image obtained from the camera will decrease. If the brightness of the reflected light is lowered, it will not be correct during the visual processing. Image. Therefore, the image processing is erroneous and the machine's patch appearance is degraded. (Individual nozzle center test does not pass; component image processing is error-prone and is fixed to individual nozzles.)

Gently wipe the nozzle with a soft cloth or paper (use a cloth or paper that wipes the lens).

Note: Do not wipe the reflective surface with a dirty cloth, if this will cause image problems. If the foreign matter is difficult to remove, replace the reflective surface.

· throwing box and waste box (every 8 hours)

· throwing box

Components that are considered bad by the image processing system or that are not placed will be thrown in the throwing box. Check the throw box and clear the throw. (You can judge the condition of the machine by checking the throwing, whether the PD is written correctly,

Whether the components are good, how the vacuum of the machine is, and so on. )

·Waste box

The strip is cut and pipetted into the waste bin. A lot of production will occur every 8 hours

The waste belt, so the waste bin must be cleaned every 8 hours. (If it is not cleaned up in time, the waste bin space will be occupied, which will cause insufficient vacuum, the waste belt will be scattered and the components will be sucked poorly.

 

·Waste box

When the strip is cut, the waste bin will be drawn through the vacuum line. If this channel is blocked, the tape will be blocked and the reliability of the component's suction will be reduced.

If it is found that the machine suction material is irregular in production, check if the area is blocked. Do not use an air gun to clean it, use a vacuum cleaner to clean it.

·Feeder (every 3 months)

Feeder's regular maintenance and maintenance is extremely important to ensure the quality of the patch: the Feeder in use on the production line must be within the warranty period; the Feeder in the maintenance area requires a clear status indication; all feeders do After the PM is completed, it must be calibrated before it can be used online.

 

Fourth, component patch - patch quality monitoring

·SMD quality inspection

The printed circuit board after the patch must be inspected after the equipment is installed and repaired. At least the following items should be checked.

content:

· Location of components

The location of the components refers to the quality standard IPC-610-D of printed circuit board SMD component patches.

Components that are not within the specified tolerance limits must be removed with a solder holder; manual correction of the component location is not permitted.

The cause of the defect must be clarified and corrective action taken.

·Components are missing

Missing components are not allowed to be manually subsidized onto the board. The cause of the defect must be clarified and corrective action taken.

 

·Impurity, scattered components

Impurities and scattered components must be removed from the printed circuit board with a soldering tin. The cause of the defect must be clarified and corrective action taken.

· Damaged components

Damaged components must be removed. The cause of the defect must be clarified and corrective action taken.

·Reuse of components

Components sorted from the placement machine are not allowed to be reused.

·quality control

Quality personnel should perform detailed auditing on each part of the placement process:

Equipment maintenance record and identification status;

All operations must follow installation regulations and ESD directives;

After the transformation, the first board was 100% visually inspected to confirm whether the patch had defects such as wrong part, missing, misalignment, tombstone, etc.

Whether the component workbench and the conveyor belt have scattered components, etc.

 

· Process-related production materials use regulations

Follow the rules for the use of detergents and greases

Follow the hazardous materials regulations for the patch adhesive Heraeus PD 860002 SPA

 

V. Component SMD——Identification and Analysis of Feature Defects

· The component placement station mainly has the following defects:

Incorrect polarity, wrong parts, missing components, misaligned components, component damage, tombstone

 

If you need the machine,please contact us:

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www.pcb-soldering.com

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SMTfly Electronic Equipment Manufactory Ltd