Tie-bar-less technology optimally utilises efficiency potentials

The exhibition booth of ENGEL at Interplas 2018, held from June 20 to 23 in Bangkok, Thailand, was focused on medical technology. Pipette tips were produced in the cleanroom version of an automated production cell. This sophisticated application illustrates how extremely quality-sensitive products can be manufactured at the lowest possible price per unit. Also shown in Bangkok: The intelligent assistance systems from ENGEL's inject 4.0 programme, which make it easy for the operator to maintain a high degree of parts quality without expert knowledge.

As pipette tips are used in fully automated analytical systems, reproducible product quality is the highest priority.

The medical technology sector in Thailand is developing very dynamically. One strong driver of this development is medical tourism from neighbouring countries, which is continuously raising the capacity of medical practices, clinics and medical service providers. The government support investments that help to develop Thailand to become a medical hub for Asia and to produce medical products in the country. Equipment suppliers are benefiting accordingly. In particular, consumables and diagnostics accessories such as pipette tips are already manufactured locally.

Because the pipette tips are used in fully automated analytical systems, reproducible product quality is the highest priority. As mass-produced parts, however, they are also under especially high cost pressure. In order to combine a stable process with high efficiency, the integrated and fully automated production cell at ENGEL's exhibition booth utilises various efficiency factors. With an extremely compact footprint, it integrates a tie-bar-less ENGEL e victory 170/80 injection moulding machine featuring 800 kN of clamping force, a hydraulic clamping unit, and an electric injection unit, with a 32-cavity hotrunner precision mould by Wellmei (Dongguan, China), and a high-speed automation by Waldorf Technik (Engen, Germany).

Tie-bar-less technology optimally utilises efficiency potentials
The tie-bar-less technology, which is unique to ENGEL, above all contributes to a high degree of total efficiency. Since there are no tie-bars in the way, the mould mounting platens on ENGEL e-victory machines can be fully used up to their edges. This allows for the installation of large multi-cavity moulds on comparatively small injection-moulding machines, keeping the cost of investment and operation low. In addition, the tie-bar-less technology allows for an especially close fitting of the automation to the clamping unit, thus reducing the system's footprint.

The design of the tie-bar-less e-victory injection moulding machine already ensures a high ratio of good parts.

The high-performance automation is another key to high efficiency. In the rhythm of the injection moulding process, 32 pipette tips at a time are removed from the mould and cavity-specific groups of 96 pipette tips each are placed in racks. Every 18 seconds, 96 pipette tips are discharged from the production cell, which is enclosed to create a cleanroom environment.

The design of the tie-bar-less e-victory injection moulding machine already ensures a high ratio of good parts. The patented force divider enables the movable mould mounting platen to follow the mould in precise parallelism while clamping force is building up and ensures that the generated clamping force is distributed evenly across the platen face. On the injection side, the electric injection unit is responsible for the extreme precision when injecting the plastic melt.

To additionally compensate for fluctuations in the ambient conditions and raw material, iQ weight control is used. The assistance system from ENGEL’s inject 4.0 programme analyses the pressure in real time during the injection process and compares the measured data with a reference cycle. For every shot, the injection profile, the switchover point and the holding pressure profile are automatically adjusted to the current conditions and the injected melt volume kept constant throughout production. This is a proactive way of preventing rejects.

When producing pipette tips, the unhindered access to the mould area of the e-victory injection moulding machine allows for an especially close fitting of the automation to the clamping unit.

In order to integrate other peripheral units and moulds alongside its own automation solutions and process technologies, ENGEL has established a worldwide network of system partners. The production cell for the production of pipette tips is the result of a European-Asian collaboration. ENGEL, Waldorf Technik and Wellmei Mold have combined their know-how and experience with medical technology precision parts in order to tailor the system solution to the specific requirements of the Asian processors. By working with local suppliers, ENGEL can also guarantee high cost efficiency for challenging applications and keep the delivery time short for the complete plant.

Self-optimising injection moulding machine
Intelligent assistance systems such as iQ weight control provide an important contribution to making even complex applications manageable for the operator. Since the machine optimises itself with the help of the assistance systems, a consistently high quality of parts can be ensured without any expert knowledge. While iQ weight control automatically maintains consistent injected melt volume throughout the injection moulding process, iQ clamp control monitors the mould breathing in order to calculate and automatically adjust the optimal clamping force.

iQ flow control is the newest iQ assistance system and connects the temperature control units to the injection moulding machine in order to adjust the speed of the pumps based on actual requirements. The results are a significantly reduced power consumption and a stable temperature control process. iQ flow control is capable of actively regulating the temperature difference in all individual circuits and to automatically adjust the required flow amount for each temperature control circuit.

The growing intelligence of the machine control is a key feature of the smart factory, the goal of Industry 4.0. The systematic use of machine, process and production data and the networking of production machines all contribute to increasing the productivity, quality and flexibility of production.