Cost Impact Of Cleanliness Levels 清洁水平的成本对比
• Cleaning cost - directly proportional to level of cleanliness
•         清洁成本-与清洁度水平直接成正比
• Non-conformance level - indirectly Proportional to level of cleanliness
                   不符水平-与清洁度水平间接成比例
• Total cost = cost of cleaning + cost Of non-conformance
                   总成本=清洁成本+不符水平 
 
Selection Criteria - Cleanliness Measuring Methods
选择标准-洁净度检测方法
•         Types of contaminant污染类型
•         Types of substrate基板类型
•         Level of cleanliness洁净水平
•         Measurement speed测量速度
•         Acquisition & operating cost 获得和运行成本
•         Skill level required技术水平要求
• Features of the measurement method
•         测量方法特性
•         Non-contact, non-destructive无接触，无损伤
•         Direct or indirect 直接或间接
 
Suggested Approaches: Defining Acceptable Cleanliness Level
推荐的方法：定义合适的洁净等级
•         Baseline testing基线测试
 
•         Controlled experiment 控制实验
 
Baseline Testing基线检测
•         Measure cleanliness level of the current process当前工艺洁净等级测量
•         Measure non-conformance rate attributed to surface cleanliness表面洁净度属性不符率测量
•         If this measured rate is too high, then improve surface cleanliness process如果测量出的这种比率过高，那么改善表面清洁工艺
•         If this measured rate is acceptable, then cleanliness level of current process becomes acceptable level如果测量出的这种比率合适，那么当前工艺的清洁等级就是合适的等级
•         If this measured rate is too low, then un-improve surface cleanliness process弱国测量出的这种比率过低，那么调低表面清洁工艺
 
 
Controlled Experiment
控制实验
•         Define the desired “success” level定义需求合适等级
•         Prepare parts with varying surface   cleanliness level准备不同表面洁净等级的部件
•         Measure and record surface cleanliness levels测量并记录表面洁净等级
• Perform the next operation
•         执行下一个操作
• Measure the “success” level of the operation
•         测量这个操作的合适等级
• Correlate cleanliness level to “success” level of the operation
•         将这个操作合适等级同洁静等级关联
Example.例子
• Parts are coated with a film.
•         部件用薄膜涂覆
• “Success” = desired adhesion.
•         合适=需要的粘着系数
• “Success” level = minimum adhesion measured as peel strength.
•         合适等级=剥离强度下测量的最小粘着系数
• Establish surface cleanliness limits
•         建立表面洁净度限值
• Limits based on minimum “success” measure desired
•         基于最小“合适”需求的测量限制
• Implement cleanliness measurement method
•         实施清洁度测量方法
• Begin monitoring of cleanliness process to established cleanliness limits
•         从监控清洁工艺至建立洁净度限值
 
Surface Cleanliness Vs.Peel Strength
表面洁净度 Vs 剥离强度
  
 
OSEE Principle
光学受激电子发射原理
– Surface exposed to UV light
–        紫外线光照射表面
– UV light causes surface to emit electrons
–        紫外线光另表面发射电子
– Emitted electrons collected and converted into a voltage signal
–        发射的电子聚集并转化成电压信号
– In general, clean surface gives high emission
–        通常，洁净的表面会有更高的发射
– Surface contamination partially blocks:
–        表面污染部分阻碍：
– The UV light reaching the surface
–        紫外光到达表面
– The flow of electron away from surface
–        电子流离开表面
– Contamination causes a drop in measured signal
–        污染会引起测量信号的一个回落
 
 
How it works
它如何工作
  
 
Cleanliness Monitoring of Solid Rocket Motor (SR, M) Using OSEE
使用光学受激电子发射的Solid Rocket Motor (SRM)洁净监测
• SRM is made up of several segments of D6ACsteel, approx. 13 feet diameter and 10 feet long.
•         固态引擎电机由几段D6AC钢制成，直径约13英尺，长约10英尺
• Segments are mechanically fastened to each other with a groove/ring arrangement.
•         各段用一个凹槽/圈组合固定彼此
• This joint also houses the infamous “O” ring.
•         连接处也覆盖在“O”型圈内
• An asbestos/rubber lining covers the inside surface of SRM including the joints
•         一个石棉/橡胶内衬覆盖固态引擎电机及接头内表面
• Solid propellant is then cast into the SRM
•         然后固体推进剂被掷入固态引擎电机
• During the launch the propellant burns and generates intense heat
•         推进剂燃烧之前期间，产生高强度的热量
• Several approx. 1 square foot sections of D6ACsteel were prepared with varying degree of surface contamination
•         准备几个不同程度表面污染约1平方英尺区域的D6AC钢
• Surface cleanliness of these samples was measured and recorded
•         测量这些样品的表面洁净度并记录
• Next the lining was bonded to these sections
•         内衬边缘与这些区域连接
• Peel tests were performed to measure the adhesion strength of the lining
•         执行剥离实验是为了测量内衬的粘着强度
 
 
  OSEE Vs. Contamination Level
      光学受激电子发射Vs污染等级  
 
  Peel Strength Vs. Contamination Level
      剥离强度Vs污染等级 

Cleanliness Monitoring of Solid Rocket Motor (SRM) Using OSEE
使用光学受激电子发射的Solid Rocket Motor (SRM)洁净监测
• The predominant contaminant is HD2 grease that fluoresces
•         主要的污染是发荧光的HD2油脂
• Prior to the use of OSEE surface cleanliness was checked with black light
•         使用光学受激电子发射表面清洁之前需用黑光检测
• The lowest level of contamination that could be detected was 100mg/ft2
•         可检测的最低等级污染是100mg/ft2 毫克/平方英尺
 
• This level of contamination resulted in an average peel strength of 50 pounds per linear inch (PLI)
•         这种等级的污染导致一个50磅每线性英尺的平均剥离强度
• An acceptable level of 150 PLI was established
•         合格等级150磅/线英寸建立
• This level of peel strength corresponds to an OSEE reading of 900
•         这种剥离强度等级与读取值900的光学受激电子发射相对应
• Currently, in SRM production, this is the minimum acceptable level of OSEE reading
•         当前，在SRM生产中，这是光学受激电子发射读取的最小标准等级
 
Summary总结
•         Why monitor cleanliness 为什么要检测洁净度？
•         Types of contamination 污染类型
•         Types of cleanliness measurement methods洁净度检测方法类型
•         Most common verification/measurement methods最常用的确认/测量方法
•         Criteria for selecting a cleanliness monitoring method选择清洗监测方法标准
•         Cost impact of cleanliness level清洁度水平的成本影响
•  ,        Suggested approaches to defining acceptable limits 推荐的定义合适限值的方法
•         Example of defining acceptable limits定义标准限值示例
•         Summary 总结