- The factory tour report summarizes Stephen's visit to Taizhou Xiang Yu Machinery Co., Ltd. to investigate issues with hardness in their manufactured parts. - Testing with a calibrated hardness tester showed that the parts met the required hardness specifications after heat treatment, indicating the previous failure was likely due to using an uncalibrated tester. - Suggestions were provided to the manufacturer to appoint a quality manager, keep thorough inspection records, calibrate measuring tools, and double check tools before use to prevent future issues.

1. Factory Tour Report Dec 3rd, 2009 Prepared by Stephen

2. 1. General Information To visit a manufacturer in Taizhou area who has problem with hardness right now, make sure the current situation and help them to work out all issues. Details: 1. Manufacturer Name: Taizhou Xiang Yu Machinery Co.,Ltd Plant Address: 24#, B3, Nan Jie Cun, Jin Qing Town, Lu Qiao, Taizhou Contact: Mr Luo Hualai Mobile: 13906576812 2. Visit Date: AM8:00-PM5:00 Dec 3rd, 2009 Visit Plant: - Xiang Yu Plant - Jin Feng Plant ( Note: it's heat treatment subcontractor which is around 5 km away from Xiang Yu) Contact Person: Mr Luo Hualai

3. 2. Detailed Job Scope Rework Worms and Worm Gears -Should be inspected 100% -20% of the total 300 pcs(need to subtract some has passed and delivered) worms/worm gears have been tested by Mel last time 25% of the worms were faulty in hardness 85% of the worm gears were faulty in hardness -The manufacturer should inspect all of them after redo the Heat Treatment Confirm it with the manager Get the inspect record/report -Double check about 20% of 300 pcs to confirm when on site -Double check the accuracy of hardness tester prior to use it -Check the key dimensions and performance of rework worms/worm gears as there might be distortion after the rework. -Check the overall volume -Prepare some QC inspection paperwork and share with the manufacturer to have them do the quality in a professional way.

4. 3. Questionares for the Heat Treatment -Due to the failure of hardness, Confirm following items: a. Is the raw material right with the elements? Provide the report if necessary b. Is the Heat Treatment process used correct parameters? particularly the tempering temperature. Also check the hardness after quenching but before temperature to see whether the quenching is proper and enough. c. Is the HT ovens temperatures work well and show correct temperature or in an reasonable tolerance ? this is very common problem in my experience. d. Is the manufacturer use the calibrated hardness tester ? use a hardness standard to check it. e. Is the worker use correct way to measure the hardness ?

5. 4. Step 1- Check the hardness tester 1. Prior to do any detailed job, I checked the hardness tester which is on using by the manufacturer right now. My mothod is use a hardness standard which is HRC 44.5 in value to check the tester's accuracy. The result is around HRC 42. 2. Then I tested 6 points(3 on top and 3 on bottom surface) of the gear, the result as following: TOP: 29.5, 31.5, 31.5 BOTTOM: 31, 32, 31.5 3. As there's a deviation of 2.5 for the tester, I assume the correct value should be: TOP: 32, 34, 34 BOTTOM: 33.5, 34.5. 31.5 4. Therefore I need to change to a correct tester to verify it. PS. the final test result proved all my suspect

6. Ref: Wrong Hardness Tester which the manufacturing is using NO CALIBRATION RECORD Unfortunately the engineers didn't test and calibrate it before using it last time either, so got the wrong values.

7. 2. Step 2- Use a reliable tester for the inspection 1. We went to the heat treatment shop to use their hardness tester. Model: HR 150A Manufacturer: Shanghai Jiming Measuring Equipement Co.,Ltd Operator: a QC girl who has operated the tester for more than 5 years. so we don't need to worry about the mistake caused by human. 2. The tester is calibrated on Dec 1st, two days ago and still in the effective period. 3. For double assurance, I also have the operator tested my standard block prior to work, the result is 44.5, very fine. 4. I asked the operator tested 3 points which is 120 deg arraying on TOP/BOTTOM surface of the worm gear (total 6 points) And 3 points on the teeth of the worm Total checked 20 pcs for each which were selected at random.

8. Refer: The hardness tester which is used by heat treatment shop, it's calibrated on Dec 1st, 2009 with the record, and tested by the hardness standard too. so all values are reliable

9. Result 1: Inspect Datas for Worm Gears Part No. Top Bottom Point 1 Point 2 Point 3 Point 1 Point 2 Point 3 1 35 35.5 34.5 34 34.5 34.5 2 34 32.5 34 35 35.5 34 3 32.5 33.5 33.5 34 35 32 4 35 35.5 35.5 34 35.5 35.5 5 34.5 33 33.5 34 33.5 32.5 6 33 32.5 34 35 35.5 34.5 7 32.5 33 32 34 35 33 8 35 35 33 35 33 32.5 9 32.5 32.5 32.5 35 33 32.5 10 35.5 33 33 35 32.5 32 11 33.5 33.5 33 35.5 34.5 33.5 12 34.5 32 32 34.5 35.5 34 13 34.5 35.5 34 35.5 35.5 34 14 33.5 34.5 35.5 32.5 35.5 33 15 34.5 35.5 35 35.5 35.5 33.5 16 33.5 32.5 32.5 33 34.5 33.5 17 35 34.5 33.5 35.5 35 34.5 18 35 35 32.5 35 35 34.5 19 35.5 32.5 32 35 34.5 34.5 20 33.5 34.5 33 34.5 35.5 33 Note: 1. Select 20 pcs parts out of total 300 pcs parts at random for inspection. 2. Measure 3 points on top and bottom surface which are 120 deg array around. total 6 points. 3. When consider of some deviation and test error, all dates should be between HRC 32-35, very fine and even datas

10. Result 2- Inspect Datas for Worms Part No. Point 1 Point 2 Point 3 1 32.5 33.5 33 2 35 35.5 34.5 3 35 34 35 4 34.5 34.5 35 5 34 33.5 34 6 34 33 33 7 34.5 34.5 34 8 34.5 32.5 34 9 33.5 33.5 33 10 34.5 34 34.5 11 34.5 34 35 12 34.5 33 34.5 13 34.5 35 34 14 35 35.5 34 15 32.5 34 34.5 16 34 34 34 17 32.5 34 35 18 32.5 33 34 19 34.5 34 34.5 20 34 34.5 34.5 Note: 1. Select 20 pcs parts out of total 300 pcs parts at random for inspection. 2. Measure 3 points on the teeth area for inspection 3. When consider of some deviation and test error, all dates should be between HRC 32-35, very fine and even datas

11. Step 3- My conclusion and Suggestions So most likely the previously failure is because we used wrong hardness tester and withou any calibration. then got all wrong datas which looks much lower than it should be. Judge from the new inspection datas and a short trip to the heat treatment shop, I assume the quenching and tempering process are ok and the result is ok too. Some suggestions for the manufacturer: I suggested them to do following corrective and preventive actions: 1. Appoint a dedicated work to in charge of the whole quality issues 2. Keep all inspection records no matter for comprehensive inspection or randomly inspection. 3. Be aware of the accuracy of measuring tools, and calibrate them if necessary. 4. Doubel check befor use a measuring tool to avoid wrong datas

12. Step 4. Some Other Issues 1. Painting: Regarding the part "Housing ROD ROTATOR 3020". I see there remarked that "O-ring Surface shall not be painted" and " all other external surfaces shall be painted..." but the manufacturer didn't apply paint to upper circle surface. I am not sure whether it's necessary. as it's inside another part. 2. I also found some small rust area in no painting surface, have asked them remove it and apply some anti-rust grease before delivery.

13. Factory Tour Pictures-1

14. Factory Tour Pictures-2

15. Factory Tour Pictures-3

16. Thanks for your attention !