CNC Machines – clearing some misconceptions

Types of CNC machining

Sheet metal cutting, forming

Turret punch press

Laser

Water jet

Video

Video

Video

Turning

Video

Die - 3D milling

Video

Aerospace - 5 axes milling

Video

Production - 2D milling

Video

India machine tools – 2011 stats

India is7th largest consumer of machine tools in the world.12th largest producer4th largest importer

Growth31 % growth in consumtion68 % growth in imports

Types of machines80 % of machines are CNC, 20 % non-CNC75 % is metal cutting, 25 % metal forming

Some common misconceptions

Most industries do 3D, 5-axes machining.

A few low tech industries do 2D machining.

Misconception 1

Which of these partsdo you see most oftenon shop floors ?

What type of machining do you mainly see in these firms ?

Production machining accounts for 90 % of CNC milling.Die milling / 5-axes milling for 10 %.

3D, 5-axes machining is 'high tech'.

2D machining is 'low tech'.

Misconception 2

2D 3D

Cycle time reduction - importance High Low

Shop documents - importance High Low

Process - complexity High Low

Tool selection - complexity High Low

Part geometry - complexity Low High

Cutting parameters selection - complexity High Low

Nothing is 'high tech' or 'low tech'.Each type of machining has its own complexity.

CAM software designed for 3D / 5-axes machining can also program for 2D machining.

Misconception 3

CAM software for production machining

Must support wide variety of machining operationsMust support wide variety of toolsMust have features to reduce cycle timeMust have features to check and optimize spindle power usageMust generate shop documents automatically

CAM software requirement for each application is different.Same software cannot do both.

CAM software for 3D/5-axes machining

Must have 3D CADMust be able to machine complex surfaces

Programming is the main task in CNC machining.

Misconception 4

Programming is NOT the main task.Programming is just one of the steps.

Misconception : Most industries do programming by CAM software. Only a few small industries program manually.

Fact : Most industries program manually.

Misconception 5

Skills required in industry

The gap – institute to industry

Main cause of poor productivity on shop floors is lack of knowledge of tooling, cutting parameters selection.

Fact : 95 % of experienced CNC personnel on shop floors do not know the full form of the commonly used word 'carbide'.

Institutes concentrate on teaching programming, students think this is all that is required.

Fresh engineers are as a result useless in industry, take 6-12 months to learn required skills and be useful.

Skills required in industry

Machine construction Machining operationsToolingCutting parameters selectionManual programmingProgramming using CAM software (optional)