CNC Machines information CNC Articles Machine Tools CNC Software Articles

Conmed Linvatec Biomaterials is using a Krauss-Maffei Berstorff Ultra Glide laboratory extruder to produce biodegradable compounds based on lactic acid.

The Finnish-based manufacturer of medical products opted for the extruder as it meets stringent requirements of this special field of industry.

For the production of implants used in the human body, such as screws, plates or pins applied for fixing bone fractures, for instance, cleanroom conditions are a definite must.

The Krauss-Maffei Berstorff extruder was designed in strict compliance with the Good Automated Manufacturing Practice (GAMP), an internationally accepted guideline for the validation of computer-assisted systems in the pharmaceutical industry.

The control system used for this application has to operate like a black box documenting all production steps involved.

Implants based on polylactide plastics fix the bones in position just like conventional implants offering at the same time the decisive advantage that they need not be removed in a second surgery after the fracture has healed.

As they are made of absorbable polymers, they enhance the fracture healing process so that the patient is relieved from pain within less time.

Krauss-Maffei Berstorff said that this extruder has been proven for producing PLA compounds.

The Ultra Torque model in the ZE series is characterised by high drive power for screw speeds of up to 1,200rev/min and high material output rates.

At the same time, the machine ensures rapid and careful processing, which is of particular importance with these compounds.

With the Ultra Glide version, the extruder screw is extracted within a minute from the processing section, which facilitates access to the screw and substantially reduces the cleaning time in the case of a recipe change.

Posted by admin under extrusion | No Comments »

Holton Crest has introduced the Holton2 range of continuous rotary extruders.

The three models in the range - the HC1100, HC2200 and HC4000 - are wholly European-sourced.

Many of their features can be integrated into Holton’s existing products and designs for material handling, material conditioning and product handling.

Posted by admin under extrusion | No Comments »

The Inoex Advantage system for automated dimensional product changes during production of plastic pipes is a retrofitting technology that can be delivered as an integral part of an extrusion line.

Chinese extrusion specialist Liansu has decided to offer this combination.

On request, extrusion lines are now equipped ex works with an integral Advantage system.

On this ground, a cooperation was set up with Inoex.

The Liansu Group manufactures plastic pipes and extrusion lines.

Liansu’s machinery manufacturing division engineers, produces and supplies extrusion lines including extrusion dies for processing PVC, PP and PE.

The cooperation contract set up with Inoex covers the full integration of Advantage when requested by the customer.

This solution will be added to the product range offered by the China-based company.

Presently, Advantage still has its own operation terminal.

In the future, the plan is to integrate the control unit for automated dimensional changes into Liansu’s extruder control.

The cooperation agreement also encompasses other Inoex systems: the gravimetric product series (Saveomat) and ultrasonic measuring systems (Aurex).

Posted by admin under extrusion | No Comments »

Putnam Plastics has developed technology for producing thin walled, large diameter, low durometer urethane extrusions.

Commonly used in minimally invasive medical devices, such extrusions have been fraught with design challenges.

The development of this advanced fabrication technology has provided medical-device OEMs with increased design freedom and production capabilities and clinicians with more sophisticated tools with which to improve the quality of care for their patients.

The motto in many medical-tubing applications is ‘bigger, softer, thinner’.

With the continuing evolution of less invasive surgical techniques, clinicians are pushing device engineers to fit more and more technology through a working channel of limited size.

New techniques such as Notes (Natural Orifice Transluminal Endoscopic Surgery) and SPA (Single Port Access) are driving device designs consisting of fewer and larger access points, with the goal of maximising the working space within.

These advanced techniques also require considerable articulation of the device within the body with minimal operating forces.

For the device engineer, this results in the need to use on the outer body of the device extrusions that are larger in diameter, have thinner walls and are highly flexible and durable.

From a functionality standpoint, thermoplastic urethane is a prime choice for such demanding applications.

However, when considering design-for-manufacturability, there are tremendous challenges to overcome.

Byron Flagg, product manager at Putnam Plastics, said: ‘As diameter increases and wall thickness and durometer decrease, the extrusion process becomes more unstable.

‘This instability, which results in larger tolerances and lower yield rates, has forced device engineers to compromise their designs accordingly.

‘Even after fabrication, such extrusions are extremely difficult to handle without contamination or damage, resulting in quality non-conformances, higher unit price and overall lower value for the customer.’ After extensive development, Putnam Plastics has implemented a proprietary combination of custom equipment and advanced processing conditions to address the historical challenges involved in the fabrication of this type of tubing.

Improved process stability results in a larger design envelope for device engineers; improved material-handling techniques reduce costs by increasing yields and product quality.

Take, for example, any given 80A durometer urethane extrusion with a diameter greater than 0.5in (12.7mm).

If the minimum feasible wall thickness had previously been 0.015in (0.38mm), it has now been reduced to 0.003in (0.08mm).

If the OD tolerance had previously been +/- 0.010in (0.25mm), it has now been reduced to +/- 0.002in (0.05mm).

These tangible improvements reduce tolerance stack-up and allow more efficient device design.

After fabrication, advanced handling techniques allow the finished components to move on to the next stage of manufacture, free of defects or contamination.

This new capability is widely applicable across a broad range of custom extrusion designs with the greatest impact in ODs greater than 0.500in and wall thicknesses of less than 0.015in in urethane durometers lower than 90A.

As with all of Putnam Plastics’ custom fabrication technologies, this new capability can be applied cross functionally and integrated into designs that include features such as co-extrusion, multi-lumen and wire reinforcement.

The end result is a wider envelope of possibility for device-design engineers to meet the functional needs of clinicians without compromise.

Posted by admin under extrusion | No Comments »