[PPT] - LUREN Precision Co.LTD. www.luren.com.tw Head Office: Via Marconi, PowerPoint Presentation

SLIDE 1

Head Office: Li Hsing Factory Location: Hsin Chu Science Park - Taiwan www.luren.com.tw

LUREN Precision Co.LTD.

Distributor for European market Head Office: Via Marconi, 8 Viganò Brianza (LC)- Italy www.fubri.it

SLIDE 2

Luren Hob Resharpening Machines

CNC Hob Resharpening Machines producing by Luren LHG-3040 ---- LHS-3040 ---- LHG-2540 ---- LHG 1520 LUREN

Distributor for European market

SLIDE 3

LUREN

With this presentation we want to inform about:

Basic of hob resharpening operation
Working condition
Description of Luren hob resharpening machines

The most important characteristic of Luren resharpening machines are:

High performances
High tech design and components
High flexibility
Easy to use
Low cost

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SLIDE 4

LUREN

Basic technical information about of hob resharpening operation

The accuracy of the hobbing process to a large extent on good hob resharpening and the performance of hob is very much affected by the type of resharpening carried out. If a hob is resharpened under incorrect working condition, it may at times result in tooth breakage. We examine now some aspects of this important operation. The maintenance of the hob is a very delicate operation that must be carried out by a efficient machinery and modern equipment. First examine the definition of the errors that may be generated when resharpening according to the DIN 3968 normative.

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SLIDE 5

LUREN

The error of profile and position of the tooth face

u = the movement of the resharpening face in relation to the radial plan when sharpening with a positive rake angle. In radial sharpening the u value is zero. h = useful tooth depth e = profile error found

Gash radial alignment

(microns) Class Module 0,6-1 1-1,6 1,6-2,5 2,5-4 4-6,3 6,3-10 10,1-16

AA 10 10 12 16 20 25 A 12 16 20 25 32 40 50 B 25 32 40 50 63 80 100

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SLIDE 6

LUREN

Error of profile generated on the workpiece

Negative rack angle Positive rack angle

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SLIDE 7

LUREN

The indexing error between two consecutive flutes

Indexing between gashes (two adjacent teeth)

(microns) Class Module 0,6-1 1-1,6 1,6-2,5 2,5-4 4-6,3 6,3-10 10,1-16

AA 10 10 12 16 20 25 A 12 16 20 25 32 40 50 B 25 32 40 50 63 80 100

Must be measured half way up the tooth

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SLIDE 8

LUREN

Spacing between two non adjacent flutes

Maximum indexing error between any two teeth

(microns) Class Module 0,6-1 1-1,6 1,6-2,5 2,5-4 4-6,3 6,3-10 10,1-16

AA 20 20 25 32 40 50 A 25 32 40 50 63 80 100 B 50 63 80 100 125 160 200

This is the cumulated indexing error of the flutes

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SLIDE 9

LUREN

Error of profile generated on the workpiece

Indexing error of the flutes produces irregular profile

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SLIDE 10

LUREN

The direction error of the flutes

Accuracy of gashes

ver 100 mm

(microns) Class Module 0,6-1 1-1,6 1,6-2,5 2,5-4 4-6,3 6,3-10 10,1-16

AA 50 A 70 B 100

This error is measured in a length of 100 mm

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SLIDE 11

LUREN

Interference between grinding wheel and hob

Hob Gear

Sharpening a hob with helical gashes using a grinding wheel that has a rectilinear cutting line, the face that is generated will be slightly crowned because

f the interference of the

grinding wheel with the helical gash. The larger the helix angle of the gash and the larger of the diameter of the grinding wheel, the greater this convexity of the resharpening face will be. This is why resharpening machines which works helical hobs must be equipped with a special dressing unit to profile the grinding wheel, so as to generate the same convexity and compensate for the interference

phenomenon. A hob with a convex cutting face will produce a gear tooth

with more material on the tip and at the root.

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SLIDE 12

LUREN

Working condition in resharpening

a)- Movement below centre which generates a positive cutting angle b)- Movement above centre which generates a negative cutting angle

The u movement of the grinding wheel in relation of the hob depends both on the rack angle and on the hob diameter where the following applies:

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SLIDE 13

LUREN

Working condition in resharpening

The sharpened surface roughness must be as low as possible so that the cutting edge is not irregular. If this were the case, wear and chipping would form with more

ease. The tolerable roughness is a

maximum of Ra = 0,20 microns If the roughness is higher the wear of the cutting face proceeds faster In order to obtain a lower roughness the working conditions must be chosen properly Ra= 0,15

Rz = 1,12

Ra= 0,35

Rz = 2,18

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SLIDE 14

LUREN

Working condition in resharpening

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The roughness is strongly influenced by grain size

f the grinding wheel abrasive

The grain size is identified by a number, but this number has a different meaning for Aluminium Oxide and CBN (or Diamond) abrasive The two following slides show the standard size

SLIDE 15

Grit specification of Aluminium Oxide abrasive

LUREN

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Approximate diameter of the grain Indicative FEPA Number Diameter in mm Diameter in inch Indicative FEPA Number Diameter in mm Diameter in inch 36 0,500 0,0200 150 0,080 0,0030 46 0,350 0,0140 180 0,070 0,0028 54 0,300 0,0120 220 0,060 0,0024 60 0,250 0,0100 240 0,050 0,0021 70 0,210 0,0080 280 0,040 0,0017 80 0,180 0,0070 320 0,030 0,0012 90 0,150 0,0060 400 0,020 0,0008 100 0,130 0,0050 500 0,014 0,0006 120 0,100 0,0040 600 0,010 0,0004

SLIDE 16

Diamond FEPA DIN 848 CBN – FEPA DIN 848 Nominal width of the mesh (µm) ISO 565 USA - ASTM E11- 70 (Mesh) Mesh per 1” Japan JIS 6002-63 dimension µm Russia Gost 3647–71 dimension µm D251 B251 212 – 250 60 – 70 250 – 210 250 – 200 D213 B213 180 – 212 70 – 80 210 – 177 250 – 200 D181 B181 150 – 180 80 – 100

200 – 160

D151 B151 125 – 150 100 – 120 149 – 125 160 – 125 D126 B126 106 125 120 – 140 125 – 105 125 – 100 D107 B107 90 – 106 140 – 170

100 – 80

D91 B91 75 – 90 179 -200 105 – 75

D76

B76 63 75 200 – 230 88 – 63 80 – 63 D64 B64 53 – 63 230 – 270

63 – 50

D54 B54 45 – 53 270 – 325 53 – 44 60 – 40 D46 B48 38 – 45 325 – 400 44 – 37 50 – 40

B30

40 – 25

40 – 28

D25

52 - 32
Grit specification of Diamond and CBN abrasive

LUREN

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SLIDE 17

LUREN

Working condition in resharpening

Resharpening with CBN grinding wheel of High Speed Steel Hobs Some manufacturers prefer to remove all of the stock (from 0,20 to 0,40 mm) in just one pass using a reduced feed speed Cutting speed = 30 m/sec Feed speed = 200 mm/min Cutting depth = 0,20 mm Size of grit = 90 – 100 Concentration = 100 – 125 Resin alloying element Due to the low feed it’s produced a large amount of heat because the wheel works in the same area for a long time

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SLIDE 18

LUREN

Working condition in resharpening

Resharpening with CBN grinding wheel

f High Speed Steel Hobs

The following working condition are suggested with CBN wheels Phase Stock removal per stroke Feed mm/min Roughing 0,03 mm 2500 Pre-finishing 0,01 mm 2500 Finishing 0,005 mm 2500 This type of grinding wheel generally has a diameter of around 150 mm. Fast passes with limited stock removal and change of gashes so as to prevent the grinding wheel from heating up the hob teeth.

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SLIDE 19

LUREN

Working condition in resharpening

Resharpening with Diamond grinding wheel of Carbide Hobs The following working condition are suggested with Diamond wheels for carbide hobs Phase Stock removal per stroke Feed mm/min Roughing 0,03 mm 2000 Pre-finishing 0,01 mm 900 Finishing 0,005 mm 600 This type of grinding wheel generally has a diameter of around 150 mm. Cutting speed = 30 m/sec Size of grit = 64 Concentration = 100

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SLIDE 20

LUREN

Working condition in resharpening

Resharpening with Ceramic grinding wheel (HSS Hobs) The following working condition are suggested with ceramic wheels

Cutting speed = 30 m/sec
Feed speed = 2.500
Cutting depth = 0,03 – 0,05 mm (for modules up to 3 mm)
For modules over 3 mm cutting depth reduced to 0,01 – 0,02 mm.
The same characteristics are applied during the return stroke
Coolant must be abundant

Grinding wheels have a standard diameter in a range from 125 – 230 mm. The size of the grit may range from 60 to 80

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SLIDE 21

LUREN

Working condition in resharpening

Coolant must be abundant A very thin emulsifying oil which has strong cooling and rinsing abilities although care must be taken not to cool the work area too drastically. Even when the amount of material removed is limited and the feed is quick, notable temperatures develop at the point of contact. If this area were cooled too violently by the liquid jet, the change in temperature would be too drastic and this could be damaging. It is better to use a low viscosity oil which has good cooling abilities but which is a little more gentle. The best oil must be a viscosity between 5 and 10 cSt at 40°C In the Luren Hob resharpening machine, the capacity of the tank is 300 Liters. The quantity of the coolant in the working area is: 120 liters/min

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SLIDE 22

LUREN

Luren Hob Resharpening machines

Luren is producing now four model of hob resharpening machines:

Mod. LHG - 3040: universal hob resharpener for spur and helical hobs
Mod. LHS – 3040: simplified hob resharpener only for spur gashes hobs
Mod. LHG –2540: universal hob resharpener with different capacity
Mod. LHG –1520: resharpening machine for limited diameter hobs

Four models with different performances and different price in order to optimize the cost of resharpening operation

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SLIDE 23

LUREN

Luren Hob Resharpening machines

General characteristic

CNC-FANUC with the last digital technology (mod. 21.iMB)
Linear Motors and Direct Drive Motors
High flessibility : resharpening spur and helical hobs, HSS and

carbide Hobs, with ceramic and CBN wheels. The machines can be used like a profile gear grinder or like a shaper cutter grinder.

TFT colour flat screen 26,4 cm (10,4”)
Graphical operator guidance
Dialog imput tailor to hob resharpenig
Dialog for hob-related programming
CNC with Windows based operating system combined with PC for

program calculation and information storage

Quickly and easy change of grinding spindles
High rigidity

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SLIDE 24

LUREN

Luren Hob Resharpening machines

High Rigidity

Use high rigidity T shape structure that is used on

CNC Relieving Profile Grinding Machine

Selecting high quality steel casting, ensuring stable productivity

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SLIDE 25

LUREN

Luren Hob Resharpening machines

Precisely Driven System

High-precision , high efficiency , no backlash
Minimum mechanism linkage
Lower heat generated
Lower induced vibration

Linear Motor Direct Drive Torque Motor

Build-in Motor

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SLIDE 26

LUREN

Luren Hob Resharpening machines

Work-piece Spindle

Direct Drive Torque Motor Low Speed High Torque

FANUC -

Rated Torque : 1200 Nm 260 Nm Rated Speed : 250 rpm 300 rpm Absolute Accuracy : 15 arc-sec Repeat Accuracy : 1.3 arc-sec

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SLIDE 27

LUREN

Luren Hob Resharpening machines

Oil Cooling Linear Motor

No backlash,
High reliability,
Less components,
Easy installation,
Long Life-time.
CNC Control System
FANUC Motor
MAX. Thrust 3000N

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SLIDE 28

Linear Motor

Magnet Coil

Ball-Screw Drive

Air gap A =0.5mm Servo motor Support Units Coupling Nuts Ball screw Holder Bracket for Ball Screw Support Units

Linear Motor vs. Ball-Screw Drive

Luren Hob Resharpening machines

LUREN

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SLIDE 29

Build-in Motor of Grinding Spindle

Luren Hob Resharpening machines

LUREN Liquid cold Standard Standard Rated capacity 4.6 kw (5.3 Nm) 21 Kw (35 Nm) Speed (rev/min) 2.000 – 10.000 2.000 – 10.000 CBN wheel =.D. 150 mm 150 mm Dressable grinding wheel 125 mm 230 mm

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SLIDE 30

▬ Dressable Grinding Wheel ▬ CBN Grinding Wheel ▬ Diamond Grinding Wheel

Easy changeable (BT30)

Arbor of Grinding Wheel LUREN HSK63A

Luren Hob Resharpening machines

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SLIDE 31

Fanuc Control

IPC

Ethernet

CAM Integrated System

LUREN

Luren Hob Resharpening machines

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SLIDE 32

Latest CNC Control LUREN

CNC Control Integrated with Standard PC

Windows R XP based environment
User oriented operator interface
Easy to upgrade the grinding program
Combine with PC for program

calculation and information storage.

Luren Hob Resharpening machines

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SLIDE 33

LUREN Smart Dialogue Interface Dialog input tailor to workpiece

Luren Hob Resharpening machines

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SLIDE 34

X-axis N-axis A-axis B-axis Y-axis Tailstock Z-axis(Linear Motor )

LUREN

LHG-3040

(D.D.-AC Servo Motor) Grinding-Wheel Dressing Unit

Luren Hob Resharpening machines (Standard Type)

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SLIDE 35

LUREN

N-axis ( Build-in Motor) A-axis Y-axis Tailstock Z-axis Linear Motor (DD-AC Servo Motor) Grinding-Wheel

Luren Hob Resharpening machines (Standard Type)

LHS-3040

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SLIDE 36

LUREN

Luren Hob Resharpening machines

Dimension

Front Width: 4074mm
Side Long : 3876mm
Height : 2443mm
Weight : 7000Kg

LHG-3040 - LHS-3040 - LHS-2540 5 AXIS

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SLIDE 37

LUREN

Luren Hob Resharpening machines

Main specification

Max. workpiece diameter: 250mm
Min. workpiece diameter: 20mm
Max. gash grinding depth: 35mm
Max. number of lead: 99
Max. between center distance 550mm
Max. grinding slide stroke: 400mm
Max. grinding wheel speed: 10000rpm
CNC control system FANUC 21i-MB

LHG-3040 - LHS-3040

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SLIDE 38

LHG-2540

Min./Max.workpiece 20mm / 250 mm

Max. grinding length

350 mm

Max. module

M10

Max. grinding depth

30 mm Min./max. number of gashes 1/99

Max. gash lead angle

± 35˚ Min./max. gash lead 1000 / ∞ Min./max. distance between centers 80~450mm

Max. grinding axial slide travel

400 mm

Max. workpiece weight

30 kg

Luren Hob Resharpening machines

LUREN

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SLIDE 39

Min./Max. grinding wheel diameter : 70/150 mm

Max. grinding wheel speed : 10,000 rpm
Max. grinding wheel width : 20 mm

motor : 4.6 kW(7.5kW) Voltage : 3Ø/220 V Voltage : 40 Amp Ambient temperature : 10˚C～40˚C Relative humidity: 85% Total connected load of machine : 10 kVA CNC control: FANUC 0iMD Overall dimension(LxWxH) : 2350 x 3600 x 2000 mm Weight : 4000 kg

LHG-2540 Luren Hob Resharpening machines

LUREN

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SLIDE 40

LHG-1520

Main Specification Min./Max.workpiece diameter (CBN wheel) 20 mm / 150 mm Min./Max.workpiece diameter (Ceramic grinding wheel) 30 mm / 125 mm

Max. grinding length

300 mm

Max. module

M8 (DP3.175)

Max. grinding depth

30 mm Min./max. number of gashes 1/99

Max. gash lead angle

±35˚ Min./max. gash lead 1000 / ∞ Min./max. distance between centers 80~500mm

Max. grinding axial slide travel

400 mm

Max. workpiece weight

30 kg

LUREN

Luren Hob Resharpening machines

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SLIDE 41

LHG-1520 LUREN

Luren Hob Resharpening machines

Min./Max. grinding wheel diameter :

80/150 mm

Max. grinding wheel speed : 10,000 rpm
Max. grinding wheel width: 20 mm
Capacity of the grinding wheel drive

motor: 4.6 kw

Voltage: 3Ø/220 V
Current requirement: 30 Amp
Ambient temperature: 10˚C ～40˚C
Total connected load of machine: 15 k VA
CNC control: Fanuc
Overall dimension (LxWxH) :

2350 x 3600 x 2000 mm

Weight : 4000 kg

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SLIDE 42

LHG-1520 LUREN

Luren Hob Resharpening machines

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SLIDE 43

 Module 2.35  Pressure Angle 20˚ 00 ' 00"  Flute Lead Angle 08˚ 09 ' R  Gash Lead 0˚  No. of Start 5  No. of Gashes 17  Outside Diameter 90 mm  Length 190mm  Gash Depth 6.720 mm

LUREN LHG-3040

Luren Hob Resharpening machines

CBN grinding wheel

Example of spur hob

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SLIDE 44

 Module 12.253  Pressure angle 19˚45' 00"  Flute lead angle 16˚45' 00" R  Gash lead 1332L  No. of start 3  No. of gashes 9  Outside diameter 165 mm  Length 200 mm  Gash depth 29.5 mm

LUREN LHG-3040

Luren Hob Resharpening machines

Ceramic grinding wheel

Example of helical gashes hob

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SLIDE 45

LUREN LHG-3040

Luren Hob Resharpening machines

Ceramic grinding wheel

Example of helical gashes hob

Module 4.326 26 Pressure angle 15˚13"10" Flute lead angle 40 40˚27" 7" 00" 0" L Gash lead 147.600 600 R

No. of start

6

No. of gashes

5 Outside diameter 53.1mm Distributor for European market

SLIDE 46

LUREN

Luren Hob Resharpening machines

Example of helical gashes hob

Hob Data

O.D. x Length 90 mm x 1 190mm m Module 2.35 Lead angle 8˚ 9 " R Pressure angle 20 20˚ Gashes 17 17 Material ASP30

Grinding Data

Grinding Wheel CBN Grinding Speed 5800 rpm Removal 0.15m m m In-feed speed 3000mm/ m/mi min Cutting time 9 min. 33 sec. .

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SLIDE 47

LUREN LHG-3040

Luren Hob Resharpening machines

Ceramic grinding wheel

Example of special worm hob

m:1.193

No. of start: 3

Lead angle: 17˚21'00" Pressure angle: 19˚05" 24" Lead of gashes: 121.711L Outside diameter: 15mm

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SLIDE 48

LUREN LHG-3040 & LHS-3040

Luren Hob Resharpening machines

Example of carbide hob

Hob Data

O.D. x Length 32mm x 60mm Module 0.977 7 Lead angle 1˚ 54 " R " Pressure angle 20 20˚ Gashes 12 12 Material carbide

Grinding Data

Grinding Wheel Diamond nd Wheel eel Grinding Speed 7200 0 rpm Removal 0.05m m x 4 trip =0.2 mm In-feed speed 1000m 0mm/m /min n Cutting time 12 min Distributor for European market

SLIDE 49

Helical Shaper Cutter

LUREN Module: 3.702 Inner Hole: 44.90mm Lead Angle :35.368˚ Sharpening Angle :28˚ Shank Shaper

Spur Shaper Cutter

Optional -LHG-3040 / LHS-3040

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SLIDE 50

Shaper Cutter

O.D. 157.78 78 mm Module 1.88 Lead angle 35.368 68˚ Gashes 66 66 Sharpening Angle 28 28˚ Material ASP30 Inner Hole Diameter 44.9m m

Grinding Data

Grinding Wheel Abrasive e Wheel Grinding Speed 2000rp 0rpm Removal 0.03m m x 10trip=0. =0.3m 3mm In-feed speed 5000m 0mm/m /min n Cutting time 27 min 30 sec

Hob Sharpening Machine -- Optional

LUREN

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SLIDE 51

Hob Sharpening Machine

(OPTIONAL)

LUREN

Gear Grinding Spline Grinding

LHG-3040 - LHS-3040

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SLIDE 52

Thank you for your attention

LUREN

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