Strictly-Extrusion

Two timber industry specialists bought PVCu fencepost maker Polyfence last week for an undisclosed sum. The UK company had been in liquidation following a creditors’ meeting earlier this month. The company’s existing directors, David Forsyth and Robin Byron will stay with the company following the sale.

Polyfence makes Supalite, a hollow rigid PVC fence post. Its directors invested more than £400,000 (E560,000) in two co-extrusion lines when they set the company up early last year. Byron said Polyfence went into liquidation after it had outreached itself. “We had set up to achieve significantly high sales, and were not reaching them.”

He said new owners, Richard Fawcett and Paul Phillips, hope to expand the company using the distribution network used by sister company, Dandf, which makes timber garden products.

Davis-Standard has expanded its range of economical Killion KXE winders for film and sheet applications. Applications include narrow web, blown film and laboratory scale processes. These winders are ideal for winding rolls up to 29 inches (736mm) wide for narrow web production. Single dual and multi-shaft versions are available in fixed or turret configurations. Options include cone or air shaft core location and collapsible mandrels. Most models are supplied with a cantilevered shaft for ease and speed of core removal. A special version of the winder is available for edge trim collection.
This winder can be used on any width line for line speeds up to 100 m/min and operates as a self-contained, compact unit without the complexity or size of an air system. For more information, contact Simon Dominey at sdominey@davis-standard.com.

HT Troplast has improved its polyvinylbutyrate (PVB) film introduced 20 years ago for composite security glass glazing, so that it no longer needs cooling or an intermediate PE film to prevent the film sticking to itself. The company says more product versions will follow this one for architectural glazing. Processors using the film will save cooling energy costs in storage and production areas, as well as creating an improved working environment, the company claims. Those processors that have been taking the film with an intermediate PE film will no longer be confronted by static charges as the PE film is rolled off, eliminating the risk of contamination by dust particles.

As a result of the elimination of the intermediate PE film, HT says that 66% more PVB film can be supplied on each roll, with consequent transport and storage benefits. It stresses that the new version does not cost any more than its predecessor.

VERBRUGGEN has presented its new multi-layer adapters MA-CARR and MA-CAFR. The Belgian manufacturer of flat dies and multi-layer adapters has developed a new concept of extremely flexible coextrusion adapters. The principle of the configuration cassettes and the rotating restrictor bars has been kept. The improvement is to be found in the heart of the adapter. Due to an ingenious system of sliding elements, one and the same adapter can perfectly be used for a wide range of coextrusion configuration. The system allows much bigger variations in thickness and viscosity than it ever did before, according to the company. Due to the modular concept, a total flexibility for future products is guaranteed. The more than thirty MA-CARR and MA-CAFR adapters with up to seven layers, delivered up to now, have proven their reliability and extreme flexibility.

Bruckner Formtec has formed a strategic business alliance with Illinois-based Processing Technologies (PTi). The alliance is to market and sell mono and co-extrusion sheet machinery worldwide. Bruckner Formtec currently supplies machinery to producers of high-quality thin-gauge packaging sheet, including APET, CPET, PETG and PP. Bruckner Maschinenbau, the parent company of Bruckner Formtec, purchased a division of Barmag in 1997 and merged it with Bruckner Formtec in 2001. The Barmag division holds many patents and was responsible for the manufacture and supply of large bore co-extrusion systems and high-quality high-end production machinery.
Founded in 1988, PTi has become one of North America’s leading manufacturers of mono- and co-extrusion sheet production machinery.

In an effort to cut-back its polyethylene packaging business and focus on its high barrier products, Bemis will close two extruded film plants in the US by mid-September. This follows on from an announcement in July to close its printed film facility in Illinois, also by mid-September. The two plants are located in California and Alabama.

S.K. Folien GmbH, a newly founded company, is building a factory in Eisfeld in the state of Thuringia, Germany, and investing about EURO 15m. Dirk Schmidt, the head of the company, said that production levels will start at 20,000 t/y of packaging films made from PE-HD and PE-LD. Final production levels could reach 32,000 t/y. The company plans to collaborate with the nearby recycling plant of Schwarzataler Kunststoffe GmbH.

With Vivak® HT, Makroform is enhancing its established Vivak® series of polyester sheet with an innovative type featuring a convincing property profile. The attractions of the new material are its extraordinary high temperature resistance (HT = High Temperature) of up to 91 °C and its excellent rheological behaviour. Even for difficult tasks, it can be deep-drawn without pre-drying with no difficulty thus permitting the manufacture of complex moulded articles with low energy consumption. Like all products of the Vivak® series, the new type of sheet displays superior optic, mechanical and physical properties. Of no lesser importance are the excellent value for money and the fire prevention behaviour of the thermoforming sheet. Vivak® HT is particularly suitable for all deep draw applications and vacuum moulding. For example, it can be used for the manufacture of technical articles such as neon signs, displays or dispensing machines as well as being recommended for the glazing of ski-lift cabins.

Automatically adjusted flat dies, thickness measurements and the control software – an overall solution from one supplier !

1. Automatic flat dies:

The automatic lip centring of the flat die uses innovative EMO expansion elements.

These EMO expansion-elements are differential elements witch are controlled contrary: one part of the element expands, the other part contracts. Controlled by means of energy optimised solid-state heat pump elements (thermoelectric coolers). Thermoelectric coolers (TECs) are solid-state heat pumps utilising the Peltier effect. During operation, DC current flows through the TEC causing heat to be transferred from one side of the TEC to the other, creating a cold and hot side.

In EMO’s expansion-elements there are no heating cartridges, so the average power consumption for cross profile controlling is only about 20 W. From its original length the elements are able to work in both directions (contraction or expansion). The length of the expansion-elements is according to the temperature difference between the to parts of it. Automatic die-lip adjustment is controlled via this temperature difference (equal the voltage on the TEC’s). So it is possible to create an exact temperature difference and consequently it is simple to adjust an exact length of the expansion-element.

With these elements the electronic lip adjustment range is 700 microns. Besides controlling an accurate thickness cross profile also an electronically change of the lip-gap is possible without manual adjustment, during production!

Therefore only few minutes are necessary to change from production with a die-lip gap of 0,5 mm to production with 0,8 mm gap – just by feeding a new gap distance into the operator station – the lip will move automatically to the given gap. This happens parallel across the die, and consequently the system remains stable.

This additional feature of electronically lip gap positioning is a special tool for manufacturing low shrinkage thermoforming films also when production changes are often requested.

2. Thickness measurement for film and sheet

Non-contact thickness measurement units with capacitive and eddy current sensors.

The thickness-measuring unit is equipped with a dual sensor. A capacitive sensor measures the film thickness (via dielectric constant of the film). The result of the capacitive measurement depends on the gap between sensor and roller. Therefore an eddy current sensor measures permanently the distance sensor – roller on the same axis.

So thermal expansions, tolerances of the reference roller or a possible roll bending are compensated due to permanent distance measurement.

The scanning speed is adjustable up to 300 mm/sec (speed back up to 1000 mm/sec) enables a quick new cross profile picture on the screen every 20 sec (for a 1500 mm width unit)!

3. Length- and cross profile controlling

Length- and cross profile controlling completes this overall solution. This software is installed on the PC in the thickness measurement unit. Cross-profile controlling software is necessary for the automatic die adjustment. The signal of the controller is set-value for the EMO expansion-elements. Controlling the length profile means controlling the thickness average. In this case the signal of this controller is set-value for the speed of the downstream or the extruder output.
This system enables quick changes of production, especially when EMO expansion elements are employed for automatic lip adjustment (short changing times means less wastage). This system enables to produce an alternating thickness profile during the film extrusion, so the edge trim wastage is reduced dramatically (no film traversing for winding is necessary). EMO offers a whole package from one supplier, so there are no chances for eventual interface problems - simply connect and run.

Strandex has signed up the first European licensee for its wood plastic composite extrusion technology. Silvadec, based in Arzal in France, was set up specifically to extrude wood plastic composite components. It will use the technology to make doors and outdoor components such as fence posts and decking.Silvadec chairman Philippe Crez says that the Strandex process offers flexibility in production, which will be important for the European market. He expects northern Europe to be the main market for his products.