Geometri ometrical cal produ pr oduct ct sp spe eci cific fica ati tions ons (GPS). Geom ome etr trical ical tolera to leranci ncing ng.. Tol ole erances of for f orm, m, or orientation ientation,, lo location cation and run-out Kalevi Aaltonen, Aalto University
Lect Le cture ure conte cont ent Major turning point in international business behaviour Standards support total quality management Accuracy is expenci expencive ve – too expencive? Modern measuring methods - uncertainty
SFS – EN ISO 1101 –standard Case studies: Papermachine Papermachine roller and bearing house Lessons to learn – if any? End relief - Xunzi
Geome ometri trica call tolera tolerance nces s Turn urning ing poi point nt
new ne w approa pproach ch to tole tolera rance nces: s:
• Subcontracti Subcontracting ng has major role role in production • From subcontracting subcontracting to business business partnership • CCC – Competitive Cost Countries • New methods – new tolerances • Symbiousis: dimensional tolerances – geometrical tolerances • Too tight tolerances – empty cash register • Modern measuring measuring methods methods gives gives cost cost savings savings
Geome ometri trica call tolera tolerance nces s • Companies consentrate on core core business business • Subcontracti Subcontracting ng will increase • Subcontracti Subcontracting ng gives gives major cost savings • Manufacturing process know how how is in danger danger • Tolerances and accuracy requirements define sourcing costs • Products must must have have exact equivale equivalence nce to drawings drawings and product models • Sensible tolerances – reasonable product costs
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
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
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)
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
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
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
Quality and quality management are not separate items from business Personnel
Management
Economy Customers
Quality
Technology Society Environment
GOOD PROFIT, PROFITABLE BUSINESS
QUALITY SYSTEM, QUALITY PRIZES
PRODUCTS, PROCESSES, PRODUCTION
MEASUREMENT DEVICES, CALIBRATION
LAWS, STANDARDS, MEASUREMENT ORGANIZATION
LOOK AT THE BIG PICTURE NOT THE SMALL DETAILS
MIKES
QUALITY TOOLS PARETO-CHART
SYSTEMS DO NOT ACT; PEOPLE DO!
Even the recipe is tested … it is always worth taisting
COMPETITORS
AUTHORITIES
STANDARDS OPERATION
PROCESS
QUALITY
QUALITY
AWARDS
TQM
LIABILITIES
QUALITY
PRODUCT
COSTS
QUALITY
METROLOGY
ENVIRONMENT
CUSTOMER
Tolerances equal to human hair
50 μm
Tolerances Incompetent engineer requires unrealistic tolerances to back up his career Tight tolerances = big production costs
Reasonable tolerances = small production costs
Tolerances Precision requirement defines production method = defines production costs
Competent dimensions and tolerances
• tight tolerances means extra costs • tolerances according to production method • no calculation on shop floor level • competent geometrical tolerances
GENERAL TOLERANCES Dimensional and geometrical tolerances shoud be perfect => general tolerances make dimensioning easier SFS-EN 22768-1 General tolerances for length and angular dimensions SFS-EN 22768-2 General geometrical tolerances
General tolerances for length and angular dimensions Permissible deviations for basic size range (mm) Tolerance class
0,5…3
fine
±0,05
±0,05
medium
±0,05
coarse
±0,2
very coarse
-
3…6
1000
1000.. 2000
2000.. 4000
±0,2
±0,3
±0,5
-
±0,3
±0,5
±0,8
±1,2
±2
±0,5
±0,8
±1,2
±2
±3
±4
±1
±1,5
±2,5
±4
±6
±8
6…30
30…
120…
400…
120
400
±0,1
±0,15
±0,1
±0,2
±0,3 ±0,5
Gene nera rall tolera tolerance nces s on straightne straightness ss and flatne flatness ss for range ra nges s of nom nomina inall le lengt ngths hs (mm mm)) Tolerance class
…10
10…30
30… 100
100…
300…
1000…
300
1000
3000
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
Gene nera rall tolera tolerance nces s on perpe perpendicula ndicularity rity for range ranges s of nomina nom inall le lengt ngths hs of shor shorte terr sid side e (mm) Tolerance … 100 class
100…
300…
1000…
300
1000
3000
H
0,2
0,3
0,4
0,5
K
0,4
0,6
0,8
1
L
0,6
1
1,5
2
Gene nera rall tolerance tolerances s on circular runrun-out out (mm)
Tolerance class
Circular run-out
H
0,1
K
0,2
L
0,5
Refe fere rence nce va value lues s for tur turne ned d com compon pone ents (mm)
Diameter
IT7…9
IT10…12
IT7…9
IT10…12
Ra < 6,3 μm
Ra < 12,5 μm
Ra < 6,3 μm
Ra < 12,5 μm
30…120
0,02
0,08
0,05
0,2
120…315
0,025
0,12
0,08
0,3
315…630
0,03
0,16
0,10
0,4
630..1000
0,03
0,20
0,13
0,4
Accuracy is expencive – more operations… Hole Ø 25 - drilling with twist (spiral) drill - cost: 1 € 0,010 Hole Ø 25 H8 - drilling with spiral drill - drilling with boring drill - reaming with reamer - cost: 10 €
€ Unnecessary accurary – useless production costs
IT 10
IT 9 IT 8 IT 7 IT 6 IT 5 IT 4
Accuracy
Mitutoyo Crysta Apex 9106 905 x 1005 x 605 mm, MPEE = (1.7+0.3L/100) μm CMM PH10 and MCosmos2-software machine installed and calibrated Price:
85 000 €
When measuring100 mm MPEE = 2,0 μm
Mitutoyo Legex 9106 905 x 1005 x 605 mm, MPEE = (0.48+0.1L/100) μm CMM with scanning probe MPP-100 and MCosmos3-software installed and calibrated Price:
320 000 €
When measuring 100 mm MPEE = 0,58 μm
Measurement uncertainty:
Measuring uncertainty is the test value which gives the border lines for measured value with certain probability
The borders define the system.
performance
of the measuring
Big uncertainty leads to unnecessary rejection of products, expencive development projects or accepting the defective products.
Measurement system resolution requirement is 1/10 of the tolerance zone Measurement process variation must be better than 10 % of the process tolerance zone
Because there is always a ”gray zone” the only alternative is to minimize the variation of the process so that the parts are w ithin the toleranc e zone w hen taking into account the measuring uncertainty. Statistical proc es s control, probability, the law of averages !
accepted
?
? Rejected ! Accepted !
Case study Paper machine calender
Cardboard machine ValZone calender (Metso Paper, M-real, Simpele)
Calender turned withou t online measurement and contro l system (Aalto-yliopi sto, Petri Kuosmanen)
Deviation 159 μm
Turning f eedback measuring and machining system (Aalto-yliop ist o, Petri Kuos manen)
Calender machined using the online measurement and co ntrol system (Aalto-yliopi sto, Petri K uosmanen)
Deviation 30 μm
Grinded calender withou t feedback system Aalt o-yli op is to , Pet ri Ku os man en)
Deviation 66 μm
Grinding feedback measuring and machining system (Aalto-yliopisto, Petri Kuosmanen)
Grinded calender by usin g feedback system Aalt o-yli op is to , Pet ri Ku os man en)
Deviation 20 μm
Bearing housing
Geometrical tolerancing – Tolerances of form, orientation, location and run-out Diamensional tolerances Surface roughness
Symbols for geometrical characteristics
?
Symbols for geometrical characteristics
Symbols for geometrical characteristics
?
Symbols for geometrical characteristics
Symbols for geometrical characteristics
?
Symbols for geometrical characteristics
What is SFS-EN ISO 1101 ?
Straightness a piece of cake …
What is the difference ?
Flatness of three surfaces but what is CZ ?
Let’s Google: CZ ?
CZ = Common Zone
You bet ! … Common Zone !
Position tolerance for the hole, b ut w hat i s t he let ter P an d t he ci rcle ?
Google again Letter P • p (piko-) 10 -12 • Physics p eq. preasure • P (peta-) 10 15 • Physics P eq. Power • Chemistry P eq. phosphorus • Currency p was pennies from heaven • Country code P eq. Portugal
P= Projected tolerance zone
Of course - Projected tolerance zone!
SFS-EN ISO 1101 good old story! …but repetition is the mother of learning
Bearing housing (© TU Chemnitz)
Bearing housing (© TU Chemnitz)
Bearing housing (© TU Chemnitz)
Bearing housing (© TU Chemnitz) Straightness Roundness
Flatness
Bearing housing (© TU Chemnitz)
Perpendicularity Concentricity
Parallelism
Bearing housing (© TU Chemnitz)
Roundness
Bearing housing (© TU Chemnitz)
Bearing housing (© TU Chemnitz)
Bearing housing ( © TU Chemnitz) Geometrical tolerances with roundness measuring machine
Bearing housing (© TU Chemnitz)
Bearing housing (© TU Chemnitz)
Bearing housing (© TU Chemnitz)
Symbol
Tolerances
Concentricity
Location
Parallelism
Orientation
Flatness
Form
Roundness
Form
Roughness
Surface
Length, Angle
Measure
CMM
Form measurement Surfaceroughness measurement Manual measuring devices
Bearing housing (© TU Chemnitz) Dimensions
Form
Location
Bearing housing (© TU Chemnitz)
Bearing housing (© TU Chemnitz)
Bearing housing (© TU Chemnitz)
Bearing housing (© TU Chemnitz)
LET’S GO FROM THE IRON AGE TO THE SPACE AGE
HANDICRAFTS WITH HAND HELD MEASURING DEVICES
PRODUCTS FROM THE PAST – ANTIQUE MEASURING DEVICES
PRODUCTS FROM THE PAST – ANTIQUE MEASURING DEVICES
MODERN PRODUCTS REQUIRE MODERN MEASURING DEVICES AND TECHIQUES
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
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
