A two-platen press moulds a fixed sidelight of clear polycarbonate overmolded with black polycarbonate bezel - without the cost, complexity or machine size required for rotary tooling.

Milacron is teaming with Exatec to demonstrate at NPE a new process for two-shot molding of automotive windows without the cost, complexity or machine size required for rotary tooling. A Cincinnati Milacron Maxima MG 1100 two-platen press will mold a fixed sidelight of clear polycarbonate overmolded with black polycarbonate bezel. The approach combines Milacron's creative design for piggyback injection units with an innovative mold from Exatec.

Milacron mounts the secondary injection unit on an innovative injection sled directly above the primary injection unit.

The sled is mounted to the stationary platen offering superior alignment.

'Piggybacking' the injection units reduces machine footprint and avoids compromises to the integrity of the stationary platen, pointed out Ron Hertzer, director of technology.

He said: 'There is no impact whatsoever on the compact size of the press, while we're able to eliminate the need for two holes and any effect on platen stiffness.' The integrated molding system at NPE features a Milacron robot for part take-out.

The robot places the part in an inspection box where an imaging sensor measures the bifringence of the part, then places it on a conveyor.

The Maxima is equipped for quick-mold change (QMC) with Staubli magnetic mold clamping system and a tie-rod puller.

About once an hour at NPE Milacron will demonstrate QMC capability.

'The superior parallelism provided by Maxima's direct-acting 'pancake' ram makes it an excellent press for automotive window molding,' said Hertzer.

The direct-acting ram reduces effective platen deflection by 50% compared with typical two-platen designs that build tonnage on the corners, he notes.

The large surface area of the ram distributes clamp force evenly across the back of the die plate, similar to a conventional three-platen machine.

Fully supported strain rods, long guided length, and extra large skates all contribute to superior parallelism and stability.

The short stroke of the pancake ram helps minimize cycle times with full tonnage build in 0.6s, Hertzer notes.

The Maxima design also allows fast breakaway at the end of the mold cycle with full decompression of the clamp and opening of the split nuts during cooling.

'Automotive glazing typically requires an injection/coining process to avoid stresses that can compromise optical quality,' Hertzer explained.

'In the NPE demonstration, the machine closes the mold to within less than 1mm of finished thickness of the part, then the part is filled.

Full tonnage applies compression in the mold in the coining phase.

A retractable core in the Exatec mold pulls back after the clear shot , creating the cavity for shooting the black boarder.

Shot weights are 2.15 lb for primary injection, 8.4oz for secondary injection.

The Maxima MG 1100 comes standard with Milacron's new Mosaic control.

The new control's operator panel is all-sealed, with an embedded operating system that requires no hard-disc drive or back-up power source.

It has extensive capabilities for connectivity and security, with Ethernet LAN and Powerlink, dual USB ports, optional ID card reader, and web-based or network access to process data and machine status.

The 15in touchscreen display includes standard multilingual and inch/metric support, setup wizards and a single-page overview of all critical set points.

The Mosiac control is interfaced with the robot and a particle counter on the oil system.

The Maxima design combines a compact footprint with short cycle time and energy conservation to deliver high-performance molding capability in an economical package.

It can reduce floor space by 10 to 20% over comparable machines.

The Maxima MG 1100 is 10862mm (427in) long x 3518mm (138.4in) wide.

The press can accommodate molds up to 20,240kg (44,620 lb) and 2020mm (115in) thickness, while providing best-in-class minimum mold thickness of 500mm (19.7in) (with ejector system) for exceptional application range.

The Cincinnati Milacron press offers tie-bar spacing of 1550 x 1200mm (61.0in x 47.2in) Accessibility received strong design attention to ensure optimum machine up-time and flexibility.

Complete access to the ejector mechanism, with no ram spacers, reduces set-up time, while full access above the platen enhances robot mounting and other peripherals.

All pumps and motors are positioned on the outside for easy access and service.

* Two-platen design cuts cycle time - available in 11 standard models from 1100 tonf to 4400 tonf, with custom models to 6600 tonf and more, the Maxima MG two-platen machine line uses clever design concepts to improve operator friendliness and productivity, while keeping the machine simple to maintain.

The Maxima design includes the following.

* - Features significant increases in clamp stroke and daylight within a much smaller machine footprint, across the product line.

* Allows faster tonnage build times, with drastically reduced oil reservoir requirements.

* Eliminates the four tie rod tonnage-build cylinders and their associated seals/plumbing common in other two-platen machines; also eliminates potential oil leaks in mold area.

* Offers a wide range of international injection unit sizes from 4880 to 48000, as well as multicomponent, coinjection and Milacron's patented Monosandwich molding.

All position feedback on the machine, including mold height, is via closed-loop digital position control.

Mold height setting with a single transducer on the pancake ram is simpler and more accurate than with four tie rod-mounted cylinders and four transducers, according to Milacron.

The use of a single cylinder for clamp tonnage also reduces machine complexity and service/parts issues.

Because of the minimal clamp-up oil requirement, the Maxima MG 1100 has an oil reservoir of just 2340 litres/618 gal, less than half the size of a conventional hydraulic machine.