in-process diagnostics for grinding

7/30/2019 In-Process Diagnostics for Grinding

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In-Process Diagnostics for

Grinding Process

Case Studies

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CONFIDENTIAL


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In-Process Diagnostics

Monitoring of the grinding process:a) Wheel motor power (kW)

b) Slide Position (mm)

Signals represent the grinding process as it is

happening gives the real-time signature of

the process.

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Input Transformation Output


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How does it help? Better asset utilization

Capacity Increase & Reduced cost per part By optimizing grinding cycle

Reduction of non-grinding time

Increasing wheel life

Solving process related issues

Identify and resolve process problems Burn, wheel loading, glazing, high wheel wear

Process benchmarking and machine characterization

Document the grinding process for future reference

Comparison of in-process signals between two grinding systems 2 different cycles

Same cycles, but different machine, operator, wheel, etc.

Machine characterization Axis behaviour

Deformation shapes, etc.

CONFIDENTIAL

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How does it do it?Signals What How Why

Power +

Position

Verify the grinding program Observe variations in the process

Benchmark processes

Featurerecognition

Super-

imposition

Optimize cycle time Variation of inputs to

grinding process

Power

Optimize dressing skip

Identify features process problems

Estimate grinding system stiffness

Feature

recognition

Trending

Increase wheel life

Solve process issues

Improve consistency

Position

Check axis behaviour

Identify deformation shapes of work

Monitor element deformation

Derived

analysis

Trending

Machine

characterization

CONFIDENTIAL

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Usage Aspects:

Portable unit Can be mounted on any grinding machine

of any type

Short Setup time: Can be setup on a grinding machine

within 30 minutes

High Sampling rate: Ensures real-time data capture of the

grinding process

Modular: Different sensor specs can be easily

configured based on application


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CASE STUDIES

Examples of use of Grind-Trak

CONFIDENTIAL

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BETTER ASSET UTILIZATION

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1. Reduction of non-value added time

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120

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islac

t(

)

Power(kW)

Time (sec)

OD Profile Grinding Power (kW) Displacement (mm)

Non-value

added time


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2. Reduction of grinding time (a)

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Grinding Cycle Time = 700 sec

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3.4

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0 50 100 150 200 250 300 350 400 450 500 550 600 650 700

Displacement(mm)

Power(kW)

Time (sec)

Camshaft Journal Grinding InitialPower Displacement

Steady Journals DressingDressing

Motor Rating : 7.5 kW

Machine Stiffness sufficient

Increase feed-rates

Peak power = 4 kW


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2. Reduction of grinding time (b)

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Steady Journals Dressing

Camshaft Journal Grinding After increasing feed-rates

Grinding Cycle Time = 560 sec

Peak power = 8 kW


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SOLVING PROCESS RELATED ISSUES

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1. Wheel Glazing

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Wheel glazing causing power rise (though MRR is constant)

High Power in the finishing operation indicates glazing.

Grind-Trakshows portions of the grinding cycle where the glazing takes place.

Remedial action may be taken to rectify the problem by attacking that portion of the

grinding cycle.

OD profile grinding work-material with high hardness (62 HRC)


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2. Burn

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Spike in power causing burn

Sudden spikes in power indicate potential for burning

Remedial action may be taken to rectify the problem by attacking that portion of the

grinding cycle

Crankshaft Journal Grinding


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PROCESS DOCUMENTATION ANDBENCHMARKING

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Benchmarking

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Compare grinding cycle, system stiffness, cycle time and process behaviour.

Crankshaft Journal Grinding


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Machine Characterization

Axis behaviour

Spikes generated when

there is a change in

feed-rate.

These spikes were

giving rise to step on

the component.

After Servo Motor

tuning, the spikes were

eliminated.

No more step on the

component

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SUMMARY

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Grind-Trak Sales Grind-Trak is a useful tool that helps us to

Observe what is really happening in the grinding process

Quantify parameters by measurement that were earlier not possible

Such a tool is valuable for customer relations

Optimizing the grinding system to provide value to customer (e.g.KOEL, Bosch, Texmo, etc.)

Attending to customer process related issues (BFL, HFL) As a development tool for process benchmarking (cBN OD grinding

project, Rhino project, cBN ID grinding project)

The use of such tool and the associated efforts result in

Increased customer goodwill

MGT seen as a systems solution provider than just a machine supplier Increased customer confidence

Faster customer process issue trouble shooting

More scientific approach to application engineering

Data driven approach increased customer confidence

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Grinding processThe System Approach

Ref:Subramanian K, The System Approach A strategy to survive and succeed in the Global Economy, 2000

- M Brij Bhushan, Prof. Ramesh Babu,,B.Tech Project Report - A Diagnostic Tool For In-process MonitoringOf Grinding 2012, IIT Madras.

The System Approach of looking at grinding

Finished

P

art

Operational factors Grinding cycle

Speed, feed

Depth of cut

Machine tool Structural Compliance

Kinematic Design Bearings and spindles

Work Material Geometry

Surface properties

Material properties

Tooling/ Supplies Abrasive

Coolant

Fixtures

Grinding

process Power

Displacement

Vibration

Acousticemission

Force

Temperature

Quality Form error

Dimension

accuracy

Surface

roughness

Waviness

Integrity

Process quantities

Quality parametersControl strategies

In process

monitoring Post process

monitoring

in-process diagnostics for grinding

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