| 1. Work Instructions | |
| 1.1 | Is there a revision controlled Operator Work Instruction which contains set-up information for the specific product being processed? (Score 0 if any unsigned/undated handwritten instructions or any handwritten instructions more than 48 hrs old) |
| 1.2 | Are Work Instructions readily available to the operator and are they followed at Wave? |
| 1.3 | Do Set-Up Sheets specify the Solder, the Flux, and the thinners (as applicable) to be used? |
| 1.4 | Do Set-Up Sheets specify the Spray Flux parameter settings such as delay, duration, traverse speed, pressure, etc? |
| 1.5 | Do Set-Up Sheets specify the Pre-Heater set points and the Solder Pot Temperature and are they the same as those on the machine? |
| 1.6 | Do Set-Up Sheets specify the Conveyor Speed and is it the same as that in the program? |
| 1.7 | Do Set-Up Sheets specify the Lead Clearance and is it the same as that set by the machine? |
| 1.8 | Do Set-Up Sheets specify Wave Type (Chip/Lambda/Omega) to be used? |
| 1.9 | Do Set-Up sheets specify the Solder Pot Hot Air Knife Pressure and Temperature settings? |
| 1.10 | Do Set-Up sheets specify if the Finger Cleaner must be on? No Finger Cleaner = 0 |
| 1.11 | Is the machine Program Name specified on the Work Instruction or set-up sheets? |
| 1.12 | Do the all the above wave parameter settings correspond to those settings on the machine? |
| 1.13 | Are Generic Wave Set-Up Parameters documented? These are the parameters which are not changed for product changeovers. |
| 1.14 | Do these Generic Wave Set-Up Parameters include, pressure settings, conveyor angle, etc. |
| 2. Machine Capability | |
| 2.1 | Is the flux application technology in use suitable for the product being built? |
| 2.2 | Is the wave technology in use suitable for the product being built in terms of the ability control critical parameters to achieve desired results? |
| 2.3 | Does the wave use a top side pre-heater to ensure PTH barrel fill meets IPC 610 specs given the mass of the board, carrier, and the top hat? |
| 2.4 | Are air flow controllers or a centralized control system used to balance exhaust flow rates for each individual exhaust drops? |
| 2.5 | Are exhaust flow rate ranges specified and monitored on a regular basis to insure compliance? |
| 2.6 | Is Automatic Wave Height control installed to control the laminar wave height? |
| 2.7 | Is there a Solder Pot Hot Air Knife installed and used on the wave equipment? |
| 2.8 | Is there an automatic Finger Cleaner installed and used on the wave equipment with an appropriated cleaning fluid? No FC = 0 |
| 2.9 | Is the machine Program Name revision controlled to show traceability of program changes? |
| 2.10 | Is the machine Program Name traceable to the PCB and PCBA part number? |
| 2.11 | Is access to the machine program password protected with restricted access? |
| 2.12 | Do program changes to critical parameters during machine control remain unsaved unless approved by a technician/engineer? |
| 2.13 | Is the safety equipment and protective clothing provided adequate and are they used? Must include boots, apron, gloves, face shield, etc |
| 3. Flux Application | |
| 3.1 | Is flux applied using either a fixed nozzle or moving nozzle spray application method? Any other application method = 0 |
| 3.2 | Can the sequence of; detection, delay, trigger, duration, and stop, be clearly explained by a technician? Other method = 0 |
| 3.3 | Is the detection, delay, trigger, duration, and stop, controls performing as expected? Other method = 0 |
| 3.4 | Is there a feedback link between the conveyor speed and the flux applicator to auto-compensate for changes? Other method = 0 |
| 3.5 | Is there an automatic sensor that indicates when a flux drum is near empty? |
| 3.6 | Is there a method to determine if the quantity of flux applied to the board to ensure it adequate? Not too much and not too little. |
| 3.7 | Is there a test used to check the coverage of flux applied to the board to ensure it is sufficient? |
| 4. Wave Set-Up | |
| 4.1 | Has specifying the Solder Pump Speed value been discontinued as a way to achieve the desired Wave Height? |
| 4.2 | Is the relationship between Wave Height set-up and Contact Area/Length known for the product being processed? |
| 4.3 | Is there a Quartz Plate available to verify Contact Area/Length achieved for the board being processed? |
| 4.4 | Is the documented Contact Area/Length being achieved for the Wave Height set-up used? |
| 4.5 | Does the shape of the Contact Area indicate parallelism? |
| 4.6 | Does the Contact Length coupled with the Conveyor Speed, achieve the documented dwell time requirement? |
| 4.7 | Is there evidence that Contact Area/Length and shape verified after Solder Pot removal and replacement, and maintenance? |
| 4.8 | Is there evidence that the Contact Area/Length and shape verified on addition of solder or on adjustment of lead clearance? |
| 4.9 | Does the board/pallet exit the Solder Pot in the stagnant area for the set conveyor angle and lead clearance? |
| 4.10 | Are all conveyor Fingers in a good state of repair? |
| 4.11 | Is the quantity, type and spacing of each Finger design defined for the conveyor? |
| 4.12 | Has the pot been set up to run with an intermittent wave so as to reduce dross build up? If gap between subsequent PCBAs too small, score 1 |
| 4.13 | Does the level of Dross in the pot suggest that the pot is dedrossed at least once every 8 hours? |
| 5. Temperature Profile | |
| 5.1 | Is there available a Temperature Profile for the product currently being built? |
| 5.2 | Is the Temperature Profile assessable and readily available to operators / technicians as and when required? |
| 5.3 | Were the Pre-Heat Set Points, Conveyor Speed, and Solder Temperature logged for that Thermal Profile when it was conducted? |
| 5.4 | Do the Set Points, Conveyor Speed & Solder Temp written on the Thermal Profile correspond to the current Machine settings? |
| 5.5 | Is there available an Engineering based specification to detail the acceptable process window for Temperature Profiles? |
| 5.6 | Was the Engineering based spec. derived from the Flux manufacturer’s recommendations but controls to a narrower window? |
| 5.7 | Does the product Temperature Profile fall within the Engineering based specification for the process window? |
| 5.8 | Does the product Temperature Profile fall within the Engineering based specification for glass transition temperature requirements? |
| 5.9 | Can any excursions outside of the process window be justified and supported with hard evidence and logical analysis? |
| 5.10 | Does the product Temperature Profile meet the requirements of the SMT components already attached to the PCBA? |
| 5.11 | Are the boards used to establish the initial Thermal Profile kept as engineering samples? |
| 5.12 | Have at least five thermocouples been used at various points on the board to establish the Thermal Profile? Note* |
| 5.13 | Is there a documented and systematic approach used to identify the most appropriate locations to attach the thermocouples? |
| 5.14 | Is there evidence that each thermocouple ball was bonded to a board joint using Hi Temp. Solder or Conductive Epoxy? |
| 5.15 | Is the top side Temperature Profile low enough to prevent secondary reflow? Must be below 160 degrees C. |
| 5.16 | Has a Calibration Profile been established in order to detect machine long term performance degradation? |
| 5.17 | Is there a documented frequency for running a Calibration Profile and was it established based upon historical performance data? |
| 5.18 | Is there evidence to demonstrate that Calibration Profiles are conducted and that records are up-to-date? |
| 5.19 | Is the practice of comparing the current Calibration Profile to the Standardized Calibration Profile used to identify changes? |
| 5.20 | Is the current Calibration Overlay/Profile used to determine if a variation in the wave’s thermal characteristics has occurred? |
| 5.21 | Is the current Calibration Overlay/Profile used to determine if a variation in conveyor speed has occurred? |
| 5.22 | Is there evidence to demonstrate that action was taken when the Calibration Profile was different to the Standard? |
| 5.23 | Is a standardized tool, like a WaveRider, used with a standardized profile to conduct a Calibration Profile? |
| 6. Solder Analysis | |
| 6.1 | Is there a documented frequency for conducting Solder Analysis and was this frequency established based upon historical results? |
| 6.2 | Is there evidence to demonstrate that Solder Analysis records are up-to-date? |
| 6.3 | Does the Solder Analysis results suggest that contaminants in the solder pot are within acceptable levels? |
| 6.4 | Is there evidence to demonstrate that action was taken when Solder Analysis results were unsatisfactory? |
| 7. Manual Inspection | |
| 7.1 | Are outputted boards at least sample inspected post wave for wave solder defects as part of machine performance control? |
| 7.2 | Are Workmanship Standards defined for soldering, and are they accessible so that machine performance can be measured accurately? |
| 7.3 | Is Defect Density Charting used to identify the common location of defects so that actions may be take to eliminate them? This may include addition of solder thieves, pallet/carrier modification, etc. |
| 7.4 | Is there evidence of the use of at least sampling X-ray to ensure via penetration and barrel fill are to acceptable standards? |
Write a Comment