While purchasing any m/cs, buyers needs to think carefully before purchasing.
Usually we consider the high end technology but there are many other things which needs to be considered.
All equipment common points to be include while selecting SMT m/c:
1) Convenience of using equipment: The difficulty of operating system and training.
2) Difficulty of equipment maintenance: Training of equipment maintenance and possibility of self-maintenance.
3) Spare parts supply and annual maintenance costs: Use common spare parts which are easily available in market. When dealer does not have the parts at the time of equipment breakdown, long term waiting and the expiration of warranty cause higher cost for replacement parts.
4) Equipment Safety: Accident prevention safety system.
Screen Printer:
1) Available frame sizes: Free Size response is available Min. 650 × 550mm and Max. 736 × 736mm.
2) Limit to PCB size: The limit to lower and higher PCB sizes.
3) Quality: Repeat print quality, (metal mask defective ratio) → penetra5on of solder paste (fine pitch 0.4phich below, BGA 3Ø below)
4) Printing cycle time: Inspection time with two ways: one includes time with 2D inspection and another excludes time with 2D inspection.
Mounter-
1) Expected production capacity from applied product: The production capacity with loss time allowance. Since SMT equipment has different mounting methods and according to each brand of equipment and characteristics, suitable use of equipment depends on the production of PCB type and characteristic of each company.
2) Accuracy → Quality: Mounting precision. Mounting precision of equipment depends on how precisely camera images (vision) recognize the parts and how accurately the motor of X, Y axis calculates the moving distance per pulse.
3) Limit to PCB size: Limit to the lower and higher PCB sizes.
4) Part recognition (vision) method:
· Front light: Recognition is reflected by the amount of light → It has accurate precision, but easily affected by external environment and the changes set by dissimilar parts.
· Back light: Recognition by part’s shadow→ It can recognize the subtle changes caused by shadow of part but the precision is less.
· Laser: Used to recognize parts that require high precision. Subtle change of the components is very sensitive. Currently three kinds of equipment are used to recognize the extent and determine mounting of parts.
In actual production environment, productivity and the loss of material is directly linked to the responsiveness of equipment and precision in loading.
The existing standard shape of parts in electronics is rapidly changing into various shapes which are continuously developed and released. Mounter manufacturers develop and upgrade vision software responding to the new parts and provide to client. Such support should be checked by us.
Reflow:
1) Difference between setup and actual temperature: If big gap occurs between set up temperature and measured temperature in the equipment, there is temperature loss in the reflow, thus it is most important to maintain a stable temperature.
2) Composition of temperature control zone: For possibility of production with lead free solder most appropriate number of zones would be 7 to 8 zone, with separate zones for cooling.
3) Start up time: After vacation or off day, when equipment is powered on from the off position, the time is required for reflow oven to reach set temperature in different zones till stable production is possible. Among SMT line equipment, the reflow oven takes the longest time to become operational for production. The down time to begin production mostly depends on the start-up time of reflow oven.
4) Heating methods: Bench marking and checking equipment are required as there are unique and individually designed type of equipment by different reflow oven manufacturers. A detailed review of equipment is required, since more than anything else the life of heater is important.
5) Flux filter system, cleaning and maintenance of oven: In case of preheating and heating zone, most of the flux is evaporated and released by the heat in the zone, but in the cooling zone the flux gets solidified and remains there and piled up, and it is the biggest cause of failure of reflow oven conveyor and the fan. The maintenance cycle and life of equipment is determined by the quality of filter and exhaust system.
More details are available in SMT book "Essentials of SMT: Practical Know-How".
Usually we consider the high end technology but there are many other things which needs to be considered.
All equipment common points to be include while selecting SMT m/c:
1) Convenience of using equipment: The difficulty of operating system and training.
2) Difficulty of equipment maintenance: Training of equipment maintenance and possibility of self-maintenance.
3) Spare parts supply and annual maintenance costs: Use common spare parts which are easily available in market. When dealer does not have the parts at the time of equipment breakdown, long term waiting and the expiration of warranty cause higher cost for replacement parts.
4) Equipment Safety: Accident prevention safety system.
Screen Printer:
1) Available frame sizes: Free Size response is available Min. 650 × 550mm and Max. 736 × 736mm.
2) Limit to PCB size: The limit to lower and higher PCB sizes.
3) Quality: Repeat print quality, (metal mask defective ratio) → penetra5on of solder paste (fine pitch 0.4phich below, BGA 3Ø below)
4) Printing cycle time: Inspection time with two ways: one includes time with 2D inspection and another excludes time with 2D inspection.
Mounter-
1) Expected production capacity from applied product: The production capacity with loss time allowance. Since SMT equipment has different mounting methods and according to each brand of equipment and characteristics, suitable use of equipment depends on the production of PCB type and characteristic of each company.
2) Accuracy → Quality: Mounting precision. Mounting precision of equipment depends on how precisely camera images (vision) recognize the parts and how accurately the motor of X, Y axis calculates the moving distance per pulse.
3) Limit to PCB size: Limit to the lower and higher PCB sizes.
4) Part recognition (vision) method:
· Front light: Recognition is reflected by the amount of light → It has accurate precision, but easily affected by external environment and the changes set by dissimilar parts.
· Back light: Recognition by part’s shadow→ It can recognize the subtle changes caused by shadow of part but the precision is less.
· Laser: Used to recognize parts that require high precision. Subtle change of the components is very sensitive. Currently three kinds of equipment are used to recognize the extent and determine mounting of parts.
In actual production environment, productivity and the loss of material is directly linked to the responsiveness of equipment and precision in loading.
The existing standard shape of parts in electronics is rapidly changing into various shapes which are continuously developed and released. Mounter manufacturers develop and upgrade vision software responding to the new parts and provide to client. Such support should be checked by us.
Reflow:
1) Difference between setup and actual temperature: If big gap occurs between set up temperature and measured temperature in the equipment, there is temperature loss in the reflow, thus it is most important to maintain a stable temperature.
2) Composition of temperature control zone: For possibility of production with lead free solder most appropriate number of zones would be 7 to 8 zone, with separate zones for cooling.
3) Start up time: After vacation or off day, when equipment is powered on from the off position, the time is required for reflow oven to reach set temperature in different zones till stable production is possible. Among SMT line equipment, the reflow oven takes the longest time to become operational for production. The down time to begin production mostly depends on the start-up time of reflow oven.
4) Heating methods: Bench marking and checking equipment are required as there are unique and individually designed type of equipment by different reflow oven manufacturers. A detailed review of equipment is required, since more than anything else the life of heater is important.
5) Flux filter system, cleaning and maintenance of oven: In case of preheating and heating zone, most of the flux is evaporated and released by the heat in the zone, but in the cooling zone the flux gets solidified and remains there and piled up, and it is the biggest cause of failure of reflow oven conveyor and the fan. The maintenance cycle and life of equipment is determined by the quality of filter and exhaust system.
More details are available in SMT book "Essentials of SMT: Practical Know-How".
