PLC, drives and HMi for Carding Aid machine

When Jim Kelly's ControlAbility and textile consultant Malcolm McMath were developing their KelMac mobile Carding Aid machine, it was IMO they turned to for the control equipment

When Jim Kelly's ControlAbility and textile consultant Malcolm McMath were developing their KelMac mobile Carding Aid machine, it was IMO they turned to for the control equipment that would help make this the most advanced and unique machine of its type.

Previous attempts by others to build such a machine were thwarted by constant problems which often seemed greater than the original task and, they were always a fixed part of the main machine.

Put simply, the new machine introduces controlled amounts of effect fibres, the little flecks of contrasting colour one typically sees in wool yarn, but it does so extremely successfully and in a way that no other manufacturer has discovered how to do.

The upshot is that much of the laborious work, cleaning, production down times and material losses are now consigned to history.

Jim Kelly recalled.

"In the early development days we looked at control products from a number of suppliers.

Only IMO offered us all of the products and the necessary degree of flexibility we required.

Their technical people, particularly Brian Mayne and James Large gave us enormous help over many months, and together we arrived at the solutions." IMO supplied equipment is crucial to the machines' operation and includes a G6 Programmable Logic Controller (PLC), an intelligent Human Machine Interface (HMI) and 3 VXM inverter drives.

On board the G6 PLC is a CNET communication card which allows the PLC to communicate with any other device.

In this instance the PLC communicates with a Load Cell Digitiser.

When introducing the effect fibres, it is essential that the amount is strictly controlled.

This is done by weight checking and it needs to be done frequently and extremely quickly.

On the KelMac machine, the Load Cell Digitiser (LCD) checks the effect fibre weight some 250 times per second! Although the process does not actually require 250 samples per second the superior IMO technology allows this to be 'averaged' out very precisely.

Once connected to a main production machine, effect fibres are loaded into the hopper of the KelMac Carding Aid.

From here they go to a wire feed roller then to a stripping roller and a feed conveyor before arriving at a pneumatic delivery fan which feeds the effect fibres into the Carding machine.

The three IMO supplied VXM inverter drives control three major functions.

The first controls the speed of the pneumatic delivery fan which introduces the effect fibres into the carding machine.

The second VXM drive controls the speed of the wire feed roller which takes the effect fibres out of the hopper and delivers them onto the fancy wire stripping roller.

The feed roller must be able to hold torque at low speeds.

Obviously the slower it travels, the more torque it needs.

The third VXM inverter drive controls the speed of the stripping roller which strips the effect fibres off the feed roller.

IMO VXM inverter drives, even without feedback control, overcome the limitations of normal AC drives which can become unstable at low speeds.

Although the stripping roller has less work to do, it still has to operate at low speed and not stall.

A feed (or weighing) conveyor delivers the effect fibres to the pneumatic delivery fan.

To enable this it is suspended on Load Cells which calculates average weights.

The feed conveyor is some 900mm long and is broken down into 20 blocks of 45mm length.

Each block can can be slowed or accelerated individually to ensure a precise delivery rate.

If the delivery rate is too high, the wire feed roller automatically slows down to reduce the delivery rate or increases in speed if the delivery rate is too low.

In either event it is extremely precise.

The superior technology of the G6 PLC enables users to write their own functions.

These are automatically stored in an array which outputs a stable instruction to the drives.

Jim Kelly stressed that once the main functions were set up, the writing of sub functions was achieved in only 3 or 4 lines of programming language.

Jim Kelly confirmed that he opted for IMO equipment because no other manufacturers' products offered the same degree of functionality and ability.

He leads a small enterprise of which he is rightly proud and he is a classically unfettered thinker whose concept was revolutionary.

His machine is unique and patent protected to defend his four year investment.

The technology helps as well.

"Once you've written your library of functions, they're there and they can't be lifted." said Kelly, who is extremely comfortable with the degree of security offered by IMO technology.

But it's not just blend ratios or the manufacturing process that benefits.

By introducing the effect fibres into the base fibres in the way it does, Jim Kelly's machine results in a stronger finished product.

Moreover, the fact that the Kelmac machine is totally portable will make it a huge hit on the shopfloor.

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