Geometrical product specifications (GPS). Geometrical tolerancing. Tolerances of form, orientation, location and run-out

Transcription

1 Geometrical product specifications (GPS). Geometrical tolerancing. Tolerances of form, orientation, location and run-out Kalevi Aaltonen, Aalto University

2 Lecture content Major turning point in international business behaviour Standards support total quality management Accuracy is expencive too expencive? Modern measuring methods - uncertainty SFS EN ISO 1101 standard Case studies: Papermachine roller and bearing house Lessons to learn if any? End relief - Xunzi

3 Geometrical tolerances Turning point new approach to tolerances: Subcontracting has major role in production From subcontracting to business partnership CCC Competitive Cost Countries New methods new tolerances Symbiousis: dimensional tolerances geometrical tolerances Too tight tolerances empty cash register Modern measuring methods gives cost savings

4 Geometrical tolerances Companies consentrate on core business Subcontracting will increase Subcontracting gives major cost savings Manufacturing process know how is in danger Tolerances and accuracy requirements define sourcing costs Products must have exact equivalence to drawings and product models Sensible tolerances reasonable product costs

5 Geometrical tolerances Partnership = win win -principle Investments according to quality requirements Open book principle rather than exploitation of subcontractor Client know how important to interpret to technical specification for subcontractor silent product know how must be traslated to geometrical tolerances Subcontractor must tutor the client in manufacturing competence

6 Geometrical tolerances and LCC Low Cost Countries = Competitive Cost Countries China phenomenon new attitude Not familiar with GPS Measuring skills are modest Geometrical tolerances measuring methods - TQM Processes have significant hidden costs Training of subcontractor gives good results production culture is hard to change

7 New processes new tolerances Manufacturing tolerances of the traditional production methods are well known and tolerancing is cost effective New methods new tolerances Cutting and sheet metal working with conventional tolerances 3D printing unknown quantity? Lasercutting is very accurate how to benefit Micromachining tolerances are unknown New procedures: casting, forging and welding with high precision (no cutting needed)

8 Geometrical tolerances Geometrical tolerance and dimensional tolerance are interchangeable according to maximum material requirement principle Who understands who dears to use? Difficulties and ignorance in geometrical toleranses leads to super tight dimensional tolerances unreasonable production costs and difficulties in manufacturing No stright rules how to veryfy geometrical tolerances COORDINATE MEASURING MACHINES CMM

9 Geometrical tolerances Inexperienced design engineer back up with unreasonable tolerance requirements Accuracy cost curve is not linear It is valuable to know the limitations of preproduction methods Every removed production step is valuable and improves productivity and profitability Proactive maintenance create cost savings accuracy remains Odd tolerances create extra back up cost

10 Geometrical tolerances Modern measuring cost savings Statistical process control is essential part of quality system Measure faster measure more accurate Complicated geometries are measureable Measuring systems cope with accurate tolerances CMM replaces hand held measuring devices Measurement instructions are part of component design Who ever makes the component he is responsible for quality and measurements

11 Quality and quality management are not separate items from business Personnel Management Quality Economy Technology Customers Society Environment

12 GOOD PROFIT, PROFITABLE BUSINESS QUALITY SYSTEM, QUALITY PRIZES PRODUCTS, PROCESSES, PRODUCTION MEASUREMENT DEVICES, CALIBRATION LAWS, STANDARDS, MEASUREMENT ORGANIZATION

13 LOOK AT THE BIG PICTURE NOT THE SMALL DETAILS MIKES QUALITY TOOLS PARETO-CHART

14 SYSTEMS DO NOT ACT; PEOPLE DO!

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16 Even the recipe is tested it is always worth taisting

17 COMPETITORS AUTHORITIES STANDARDS OPERATION QUALITY PROCESS QUALITY LIABILITIES TQM AWARDS QUALITY COSTS PRODUCT QUALITY ENVIRONMENT CUSTOMER METROLOGY

18 Tolerances equal to human hair 50 μm

19 Tolerances Incompetent engineer requires unrealistic tolerances to back up his career Tight tolerances = big production costs Reasonable tolerances = small production costs

20 Tolerances Precision requirement defines production method = defines production costs

21 Competent dimensions and tolerances tight tolerances means extra costs tolerances according to production method no calculation on shop floor level competent geometrical tolerances

22 GENERAL TOLERANCES Dimensional and geometrical tolerances shoud be perfect => general tolerances make dimensioning easier SFS-EN General tolerances for length and angular dimensions SFS-EN General geometrical tolerances

23 General tolerances for length and angular dimensions Permissible deviations for basic size range (mm) Tolerance class 0, fine ±0,05 ±0,05 ±0,1 ±0,15 ±0,2 ±0,3 ±0,5 - medium ±0,05 ±0,1 ±0,2 ±0,3 ±0,5 ±0,8 ±1,2 ±2 coarse ±0,2 ±0,3 ±0,5 ±0,8 ±1,2 ±2 ±3 ±4 very coarse - ±0,5 ±1 ±1,5 ±2,5 ±4 ±6 ±8

24 General tolerances on straightness and flatness for ranges of nominal lengths (mm) Tolerance class H 0,02 0,05 0,1 0,2 0,3 0,4 K 0,05 0,1 0,2 0,4 0,6 0,8 L 0,1 0,2 0,4 0,8 1,2 1,6

25 General tolerances on perpendicularity for ranges of nominal lengths of shorter side (mm) Tolerance class H 0,2 0,3 0,4 0,5 K 0,4 0,6 0,8 1 L 0,6 1 1,5 2

26 General tolerances on circular run-out (mm) Tolerance class Circular run-out H 0,1 K 0,2 L 0,5

27 Reference values for turned components (mm) IT7 9 IT10 12 IT7 9 IT10 12 Diameter Ra < 6,3 μm Ra < 12,5 μm Ra < 6,3 μm Ra < 12,5 μm ,02 0,08 0,05 0, ,025 0,12 0,08 0, ,03 0,16 0,10 0, ,03 0,20 0,13 0,4

28 Accuracy is expencive more operations Hole Ø 25 - drilling with twist (spiral) drill - cost: 1 Hole Ø 25 H8 0,010 - drilling with spiral drill - drilling with boring drill - reaming with reamer - cost: 10

29 Unnecessary accurary useless production costs IT 10 IT 9 IT 8 IT 7 IT 6 IT 5 IT 4 Accuracy

30 Mitutoyo Crysta Apex x 1005 x 605 mm, MPE E = ( L/100) μm CMM PH10 and MCosmos2-software machine installed and calibrated Price: When measuring100 mm MPE E = 2,0 μm

31 Mitutoyo Legex x 1005 x 605 mm, MPE E = ( L/100) μm CMM with scanning probe MPP-100 and MCosmos3-software installed and calibrated Price: When measuring 100 mm MPE E = 0,58 μm

32 Measurement uncertainty: Measuring uncertainty is the test value which gives the border lines for measured value with certain probability The borders define the performance of the measuring system.

33 Big uncertainty leads to unnecessary rejection of products, expencive development projects or accepting the defective products.

34 Measurement system resolution requirement is 1/10 of the tolerance zone Measurement process variation must be better than 10 % of the process tolerance zone

35 Because there is always a gray zone the only alternative is to minimize the variation of the process so that the parts are within the tolerance zone when taking into account the measuring uncertainty. Statistical process control, probability, the law of averages!

36 accepted? Rejected!? Accepted!

37 Case study Paper machine calender

38 Cardboard machine ValZone calender (Metso Paper, M-real, Simpele)

39 Calender turned without online measurement and control system (Aalto-yliopisto, Petri Kuosmanen) Deviation 159 μm

40 Turning feedback measuring and machining system (Aalto-yliopisto, Petri Kuosmanen)

41 Calender machined using the online measurement and control system (Aalto-yliopisto, Petri Kuosmanen) Deviation 30 μm

42 Grinded calender without feedback system Aalto-yliopisto, Petri Kuosmanen) Deviation 66 μm

43 Grinding feedback measuring and machining system (Aalto-yliopisto, Petri Kuosmanen)

44 Grinded calender by using feedback system Aalto-yliopisto, Petri Kuosmanen) Deviation 20 μm

45 Bearing housing

46 Geometrical tolerancing Tolerances of form, orientation, location and run-out Diamensional tolerances Surface roughness

47 Symbols for geometrical characteristics?

48 Symbols for geometrical characteristics

53 What is SFS-EN ISO 1101?

54 Straightness a piece of cake What is the difference?

55 Flatness of three surfaces but what is CZ?

56 Let s Google: CZ?

57 CZ = Common Zone

58 You bet! Common Zone!

59 Position tolerance for the hole, but what is the letter P and the circle?

60 Letter P Google again p (piko-) Physics p eq. preasure P (peta-) Physics P eq. Power Chemistry P eq. phosphorus Currency p was pennies from heaven Country code P eq. Portugal

61 P = Projected tolerance zone

62 Of course - Projected tolerance zone!

63 SFS-EN ISO 1101 good old story! but repetition is the mother of learning

64 Bearing housing ( TU Chemnitz)

67 Bearing housing ( TU Chemnitz) Straightness Roundness Flatness

68 Bearing housing ( TU Chemnitz) Perpendicularity Concentricity Parallelism

69 Bearing housing ( TU Chemnitz) Roundness

72 Bearing housing ( TU Chemnitz) Geometrical tolerances with roundness measuring machine

76 Symbol Concentricity Parallelism Tolerances Location Orientation CMM Flatness Roundness Roughness Length, Angle Form Form Surface Measure Form measurement Surfaceroughness measurement Manual measuring devices

77 Bearing housing ( TU Chemnitz) Dimensions Form Location

82 LET S GO FROM THE IRON AGE TO THE SPACE AGE

83 HANDICRAFTS WITH HAND HELD MEASURING DEVICES

84 PRODUCTS FROM THE PAST ANTIQUE MEASURING DEVICES

85 PRODUCTS FROM THE PAST ANTIQUE MEASURING DEVICES

86 MODERN PRODUCTS REQUIRE MODERN MEASURING DEVICES AND TECHIQUES

87 When the gentleman studies the aim is not to climb fast on the career ladders but to even as poor to live happy, as brokenhearted to maintain his hope, and when encountering happiness or hard luck to understand their limited scope and to maintain his mind bright. Xunzi

88 Lessons to learn Geometrical tolerances are the short cut to the heaven Modern measurement technique supports the use of the geometrical tolerances Networking, subcontracting and international sourcing requires geometrical tolerances Patience and deep know how are good practices to define the geometrical tolerances It is the euros that counts; no thingummies or gadget lovers are accepted Vita, si scias uti, longa est, Seneca (Life, if well lived, is long enough)

89 Acta est fabula. Plaudite! (Play is over. Applaud!) (emperor Augustus) Professor Kalevi Aaltonen Aalto University 89