PCB
MAR Tin Strip 36
MAR Tin Strip 36 is a clear, light yellow/green nitric acid based solution which is used for stripping tin or tin/lead resist from printed circuit boards. MAR Tin Strip 36 is a one component solution which has a high rate of metal resist removal. The system is designed for both automated horizontal spray systems and the chemistry can be used in a vertical soak application.
Advantages of the MAR Tin Strip 36 application:
- Anti-tarnish, anti-oxidizing and inhibiting agent
- Minimize copper etching
- Can be operated on bleed and feed system
- Leaves a clean copper surface
- Easily waste treated
- Provides a bright copper finish
- System is designed for a high metal loading
SOLUTION MAKEUP
- Spray – 100%
- Soak – Dilute 10 – 15% with water
OPERATING PARAMETERS
| Optimum | Operational Limits | |
| Concentration: | 100% | 83 – 98% |
| Operating Temperature: | 85°F | 80 - 100°F |
| pH: | <1 | <1 |
| Time | 30 seconds | 10 – 45 seconds |
WARRANTY AND DISCLAIMER: This information is based on our experience and is, to the best of our knowledge, true and accurate. MAR-Tech Holdings Inc. gives no warranty, expressed or implied and the products are sold upon condition that the purchasers will make their own tests to determine the quality and suitability of the product. Any information or suggestions are given without warranty of any kind and the purchasers are solely responsible any loss arising from the use of such information.
CONTROL
Break-Point: In spray applications, the conveyor speed should be set to maintain the break point at about 50% of the length of the chamber. Adjust the spray pressure so that both sides of the panel are stripper in approximately the same dwell time. This will insure that the tin or tin/lead is completely removed while minimizing the amount of copper dissolved into the solution.
REPLENISHMENT
The specific gravity set point for replenishment is normally between 1.26 – 1.29, depending on desired line speed. DO NOT replenish with acid.
EQUIPMENT
- Tanks:
Polypropylene , PVC, Polyethylene, Fiberglass - Heaters:
PTFE, Quartz, 316 SSL - Filtration:
Recommended to extend solution life - Agitation:
Vertical – rack bar 1” stroke back and forth
Horizontal – not required - Vibration:
Vertical – recommended
Horizontal – for high aspect work – a pre-soak is recommended
ANALYSIS
Reagents Required
- 0.1N Hydrochloric Acid
Procedure:
- Pipette 5 ml sample of solution into a 250 ml beaker.
- Add 100 – 150 ml distilled water
NOTE: the endpoint color change is from blur to yellow - Using pH meter, titrate with 1.0 N sodium hydroxide solution to a pH of 8.0
- Record the volume of sodium hydroxide used.
Calculation:
| mls of NaOH X Normality of NaOH 36 ml of sample |
= Normality of MAR Tin Strip |
The normality of a NEW solution of MAR Tin Strip 36 (at 100%) is 4.50 – 5.30.
The normality of a spent solution is between 3.50 – 3.70.
If the MAR Tin Strip 36 has been diluted, the normality and specific gravity will be lower.
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