FACTORY AUTOMATION NUMERICAL CONTROL...roboshot robonano fanuc are the inventors of cnc control. the first nc controlled version was released in 1958. this cnc control and motors platform

FACTORY AUTOMATION NUMERICAL CONTROL

Technivation

2018Objective - Process

Stability

Barry Hickman

Roboshot Applications Manager

20.04.2018

© COPYRIGHT BY FANUC – APRIL 20182

Generally in Injection moulding there are some factors that potentially can lead to process and

shot to shot weight variations and drifts.

I would like to explain 2 important areas that effect Process Stability

1. Machine movement precision , control and repeatability.

2. Check ring reaction and the potential for variable front flow and back flow of

molten material past the traditional check ring.

A Key Objective of FANUC ROBOSHOT design is Process Stability

20.04.2018


Machine movement control has improved over the years. Lets have brief and light

hearted reminder about some possible issues associated with hydraulic control

machines:

Position control via linear transducer.

• Changing temperature can influence length of the actuation bar and resistances.• Position drift over time, Cable feedback to control subject to electronic noise

• Position resolution is poor

Hydraulic valves control system pressure, proportional speed and try to stop at selected position.

• Time and cost to pre heat oil

• Unstable oil temp leads to drifts and long process stabilisation times.• Valves wear and characteristics change over time. Often become sluggish and erratic leading to

poor process stability.

Hydraulic actuating pistons

Where do we start!.. Its Wednsday morning. Time to start the machine… Picture this trepidation…..

1. Machine movement, precision and repeatability.

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4

Principle of Mould movement on Hydraulic IMM?

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Fanuc CNC Control System in Action

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CNC Controller

Linear Motor

Servo Motor Robot

Robomachine

CNC DrillWirecut Fully Electrical IMM Super precise Nano machine

Roboshot Robonano

FANUC ARE THE INVENTORS OF CNC CONTROL. THE FIRST NC CONTROLLED VERSION

WAS RELEASED IN 1958. THIS CNC CONTROL AND MOTORS PLATFORM IS OF COURSE USED ON ALL FANUC PRODUCTS AS WELL AS 60% OF ALL OTHER MACHINE TOOLS SUPPLIED WORLDWIDE.

7

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FANUC CNC now use digital Servo Motor Amplifier in conjunction with

optical cable to transfer information between motor, Amplifier and CNC

program at very high speed. This Advanced Digital Control delivers:

Incredible speed control especially noticeable at low speed precision due to

no electronic noise interference with the signals that can be troublesome

for copper cable transmission.

ROBOSHOT CNC MOTION CONTROL - Takes away the potential

machine movement variations, reduces stabilisation time associated

with hydraulic machines and surpasses the control of other electric

machines:

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Position and speed control is precisely the same for the 1st shot on a Monday morning as normal

production. I.E. unaffected by factors like oil temperature, ambient temperature.

There is no deterioration of performance over time. Speeds, control and cycle time will be the

‘same’ in many years time.

Clamp and ejector movements can be set more aggressively knowing that dampening speeds and

safety are not influenced by cold start ups. Cycle time is reduced.

Process / product stabilisation is much quicker because only melt temperature and other outside variations needs to stabilise.

A Stable Precise Machine Platform is Absolutely Invaluble for Injection Moulders who must have a Validated Process. Process changes after validation tend to be a total Nightmare

CNC Advantages continued.

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Mould Closing at Maximum speed then at 150mm mould position,

reduce closing speed to 0.1mm/sec for just 1mm then resume

closing…. Reassuring

So…. If the machine movements are so exact, Why is

there still potential for shot weight variation?

Please have a look at machine demonstration

20.04.2018


FANUC have developed a Standard Function called ‘Precise

Metering’ We refer as PM2 and PM3 that can further aid the check

ring closing response

In addition, can be extremely helpful to manage some other

moulding difficulties.

2. Check ring reaction and the potential for variable front flow and

back flow of molten material past the traditional check ring.

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13

Closing

ScrewCheck Valve

Problem of ‘traditional’ screw and check valve arrangement

Mold open / eject / mold close

Melted plastic for next shot

Plasticising

Injection

Slight front flow of mat’l until injection starts

caused by higher pressure behind check valve.

Pf < Pb

BACK-FLOW at beginning of injectionCause of fluctuation in injection volume

Material is slightly leaking until

completion of check valve closing.

Injection start

Partly closed

Closing complete.

Pf : Pressure in front of check valve

Pb : Pressure behind check valve

Precise Metering

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PM2 function

• Equalises pressure in front and behind check ring. Faster and more repeatable check ring closing potentially leading to further improved part weight stability.

• Ability to display on graph the position where the check ring has closed and review repeatability

• Eliminate the need for decompression after plasticising. = Avoid splay marks and visual defects especially on clear materials.

• Avoid drooling from hot tips or cold runners without using excessive decompression

• Great analysis tool to identify shot repeatability problems.

PM3 function

• Effectively monitors the volume of melted material in the barrel after plasticising. The check ring is already closed before injection and Injection fill phase self adjusts the changeover position so

the precise volume is injected.

• Used when very high precision thin wall applications need exceptional repeatability.

Precise Metering function. What can this achieve?

20.04.2018


16

ROBOSHOT display back-flow monitor for the first time in the world

BACK-FLOW monitor

This triangle area, height of peak and position represent back-flow

Injection pressure curve

Impossible to distinguish

closing point of check ring

BACK-FLOW monitor wave

Stable monitor wave => Stable back-flow

Back-flow Back-flow

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Precise Metering 3

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Ai - Mould Protection

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Ai - Mould Protection

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AI Mould protection and AI Ejector protection - Extraordinary sensitivity and

reaction to Mould movement abnormalities

Example of extraordinary motion control - Let us show you at the machine.

Pre Injection and clamp force reduction to reduce cycle time – Also can aid Gas

Venting, Use for Injection compression of lenses for example.

Precision metering control function - In use on 150t ROBOSHOT. Stabilise check ring

reaction, avoid splay marks and air involvement especially with clear materials. View the instant

when check ring is closed as injection begins. Great analysis tool!

Link i - Monitor all aspects of ROBOSHOT production. The 150t is being monitored today.

Please have a look.

Cellular manufacturing examples on video screen - Turn key solutions for complex

downstream operations.

Live - Demonstrations on the ROBOSHOT α-S150iA machine today.

20.04.2018


We reserve the right to make technical changes without prior announcement. All rights reserved.

© 2016 FANUC Europe Corporationwww.fanuc.eu

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FACTORY AUTOMATION NUMERICAL CONTROL...roboshot robonano fanuc are the inventors of cnc control. the first nc controlled version was released in 1958. this cnc control and motors platform