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Stitch Inspection Training. Presented by Marcie Dickson Honeywell Quality Engineer NASA Safety and Mission Assurance marcie.l.dickson@nasa.gov. Purpose.
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Stitch InspectionTraining Presented by Marcie Dickson Honeywell Quality Engineer NASA Safety and Mission Assurance marcie.l.dickson@nasa.gov
Purpose • Provide personnel with the knowledge and standards that will be required to perform work associated with the control of NASA flight hardware and soft-goods. • Stitch inspection of flight soft-goods are vital to ensuring that quality products are fabricated to specifications and to ensure a safe manned space flight program. Without inspections on the finished materials we cannot guaranty that the fabrication was actually done to the required standards. Knowing the standards and understanding how to apply these standards make sure that the soft-goods will be able to handle the desired loads and meet the form, fit and function requirements.
Knowledge Requirements • Personnel fabricating soft-goods shall know: • How to complete the Form 881 • Be knowledgeable of Sewing Terms and their definitions • Process for items being logged IN/OUT from controlled storage. • Student Quality Assurance (SQA) Stitch Inspector (SI) shall know: • How to complete the Form 881 • What information is required next to stamp (date) • Be knowledgeable of Sewing Terms and their definitions and how it applies in writing up sewing anomalies in the anomaly log • Be knowledgeable about the “Classification of Defects” and how it applies in writing up sewing anomalies in the anomaly log
Supporting Documentation • JSC CSD-A-533 Inspection and Acceptance Criteria for Stitches, Seams and Stitching • ASTM D-6193 Standard Practice for Stitches and Seams
Testing Personnel working controlled storage will be given a written test. • SQA will be required to make a minimum of 90 on the test. • Fabricator of soft-goods (without stamping privileges) will be required to make a minimum of 70 on the test. • The written test will be administered only once to any person wanting to assume the SQA responsibility. • If the person does not pass, but want to perform this task then additional training will be provided and retest will be performed if approved by test administrator. • The NASA HUNCH office will keep the test results on file.
Stamp ControlStitch Inspection (SI) • Stamps will only be issued to students who receive a 90 or better on the written exam. • Each school/class will be issued stamps for up to two students and the teacher(s). • The Controlled Storage stamp will be identified as HUNCH SI XX, were XX is the stamp number. • Stamps will be kept in a lock box in controlled storage. • Students will not take their stamps home. • If the student is not in the program the following year the stamp will be reassigned to another student the following year • A stamp log will be maintained to identify who stamps are issued to. • It is the students responsibility to ensure only approved inspected work is stamped.
Thread breaks, skips and run-offs shall be overstitched by not less than ½ inch. All seams shall be uniformly constricted and shall be free from pinholes, tears, cuts, chafed spots or other imperfections which could impair end item effectiveness. End of stitching that are not secured in other seams or stitching shall be secured by back stitched a minimum of ½ inches. All materials shall be protected from contamination such as dirt, grease, oil or other foreign matter during the fabrication process. All stitches, seams and stitching shall be inspected for quality of workmanship, and shall be examined visually and dimensionally for major and / or minor defects to determine conformance to the classification and list of defects as identified. All straps, handles, labels, Velcro and subcomponents shall be compared the assembly drawings for item orientation definition. General Stitching Information
JSC Form 881(Subassembly Process Sheet) • The purpose of the JSC Form 881 is to allow soft-good technicians and student quality assurance (SQA) the ability to document the fabrication process. • There are important pieces of information that needs to be recorded on the 881. Two of the most important are the part and serial number that appear at the top of page one. These two numbers identify the part and unit that is being fabrication. • The remaining information is also important; it is identified during the fabrication process. • As new parts or components are cut it is important that these are the correct pedigree and cut to the correct length. Therefore it is important to log the lot number, document the tools used and record the actual cut length. • Some items that are used during the fabrication process have expiration dates. These dates indicate that these products should not be used if the date is in the past.
JSC Form 881 Fields • Calibration Number: • This is a blank or column where you will log the steel scale calibration number. • Calibration Due Date: • This is a blank or column where you will log the steel scale calibration due date. • Part ______ mm: • This is a blank and it is where you will log the actual measurement of the cut part. • Date Column: • The date that this step was completed. • Tech Column: • The initials of the soft-goods technician that performed the task. • LM Column: • Where the QA stamps and dates the transaction. Every time a person uses their stamp they shall write in the date next to the stamp. • Lot Number blank: • These Blanks are found in the STEP section of the 881. Write the Lot as it appears in block 2 of the 911 tag. The 911 tag is a manila tag that is on the material when you check it out of controlled storage. • Expiration Date blank: • These Blanks are found in the STEP section of the 881. The product is no longer usable once this date is past. Write the expiration date as it appears on the 911 tag.
Anomaly Log • The purpose of the anomaly log is to document and track anomalies until they are repaired or corrected. • When the Stitch Inspector (SI) finds an anomaly the finding is logged. • It is the SI responsibility to complete the anomaly log • Part # / Part Name: Part number and name are found at the top of the 881 • Serial #: The serial number is found at the top of the 881 • Description of Finding: Using sewing terms to explain the finding and location • Disposition of Finding: Using sewing terms to explain the disposition. • Date: The date anomaly resolved • QA Stamp: The SI or QC stamp
Footnotes: • The defect shall be classified as major when it seriously affects the serviceability and/or appearance of the item, otherwise it is to be classified as a minor defect. • Puckering is evidence of tight tension, When puckering is evident, the seam shall be tested by exerting normal pull in the lengthwise direction of the seams. • When no more than three breaks or three skips or three run-offs or any combination not to exceed a total three of these defects occur within a distance of 48 inches or less and no more than three (3) broken stitches, skipped stitches or run-offs exist per each occurrence, these defects may be repaired. • Any required operation which can be corrected per drawing after the items have been fabricated shall be re-inspected. • If mission or required operation cannot be completed after fabrication, the defect shall be classified as Major. • Variation in the distance between rows of stitching that does not adversely affect the strength and/or appearance of the item shall be acceptable.
