Toshiba Machine has proposed the five new technologies to respond to the processing needs of today's plastic molding market; "Solid Clamp" clamping device, "S-Cube" injection unit, "INJECTVISOR-V50" HMI controller, "DST" automatic molding condition correction function and improved processing screws lineup, The EC-SX has been developed to incorporate these technologies.

To manufacture high quality thin-wall and light-weight molded products, the use of a high rigid clamping unit is required to minimize deflection at the time of molding. We have developed a new die clamping device ("Solid Clamp") which significantly improved the rigidity of the platens by 30%, compared with our previous clamping unit. Thanks to the use of the link line toggle (inclined toggle) which transfers the link force to the center of the movable platen, and double structure of the stationary platen (Note 1) and the movable platen (i.e., double rigid platens), uniform distribution of die clamping force can be realized. Molding with reduced die clamping force also becomes possible. (Fig. 1 and Fig. 2)

The supporting method of the moving die platen has been improved from the previous tie-bar guide method to a linear guide method (without tie-bar bushing). This new method reduces the sliding resist and linearization at the time of opening and closing. This structure is been used in applications where extremely high dimensional accuracies are required for parallelism linearization of the die platens, as in lens molding. With the use of this standard structure, the sensing function for die protection is improved due to the low sliding resistance of the movable die platen. The linearization of the mold opening and closing extend the service life of the dies. With the absence of tie-bar bushing, grease-lubrication of the tie-bars is unnecessary, as a result grease will not stick to the die set surface of the moving die nor will it drop into product drop area. The mold and working clothes of personnel are not contaminated with grease left on the tie-bars during die replacement. A clean molding environment is realized and our machines are having the highest reputation among customers all over the world. Furthermore, the dry cycle time of the Solid Clamp is reduced due to evaluation of the toggle characteristics and innovative control method of new controller "INJECTVISOR-V50" (as described later); shorter cycle time is now possible.

Note 1: The double structure of the clamping mechanism as been incorporated on all EC350SX and under.

The "S-Cube", which signifies "Simple, Steady and Smooth", is the injection unit which can achieve steady molding operations with a simple structure and configuration, and smooth motions. To achieve smooth motions, a friction-free drive system (Fig. 3) is used, which utilizes a linear guide for the sliding part of the injection ram that drives the screw.

The friction-free drive system contributes to the precise steady and smooth molding during injection due to minimized sliding resistance and the enhanced accuracy of the screw back pressure control during recovery (or metering). The smooth and steady motions are very effective during high-speed, high pressure molding in high-precision applications such as thin-walled micro-pattern forming. A significant advantage that is important with steady molding in precision molding operations is the reduction of, "dimensional error", which signifies an error of mold product accuracies when molding the same product in two or more machines. The "S-Cube" uses a digital load cell for pressure detector and correction. The individual difference characteristics of the load cell are minimized reducing the dimensional error that can be seen between multiple machines. (Fig. 4)

To accomplish steady molding in high-speed injection molding and micro-pattern forming applications where molding quality is influenced by the filling performance and holding pressure (transfer) changeover (a key point of the molding process), we developed the new controller "INJECTVISOR-V50" (Fig. 5) with shortened control speed (62.5μs) of each servo motor axis. This enhance the holding pressure changeover accuracy.

To rectify this situation, we have developed the "dynamic acceleration/deceleration control" for controlling the acceleration/deceleration characteristic of the movable platen, regardless of the movable platen position. As a result, we have accomplished high-response mold opening and closing motions without any impact, at any movable platen position and reduced the dry cycle time by up to 20%, compared with our previous system (Fig. 6)

The "RA" (Rapid Action) ejection control is incorporated as standard to accelerate the ejection response, which significantly reduces the ejection cycle time when multiple ejection strokes are required. The reduction of ejection cycle time is illustrated in (Fig. 7) when 5 ejection strokes were executed. A "Signal Customizing function" has been added, which allows random selection of an output signal to the sent to peripheral equipment. The INJECTVISOR-V50 allows for easy settings of the output conditions and output format, thus saving time and labor cost when output configurations are required between peripheral equipment and the injection molding machine.

Two automatic molding condition compensating programs have been put to practical use to maintain steady molding against variables such as a change in mold temperature and changes in lot to lot quantity of the plastic material. The first program is "DST-Press" (DST-Dynamic Self Tuning) for compensating die clamping force. During continuous molding operations, variations in die temperatures can cause changes in clamping force; "DST-Press" maintains a constant clamping force allowing for a consistent and steady molding cycle. In the case where die clamping force is required to adjust, it does not affected cycle time. The adjustment occurs during the mold full open position of the movable platen and does not affect the overall cycle time and maintaining a steady, smooth cycle.
The second program is "DST-FILL" is for compensating the molding conditions by detecting a change in the monitoring values including the holding transfer pressure and minimum cushion position. (i.e., most forward position of the screw during the injection process) Fig. 8 shows example where a short shot (i.e., defective molding condition where filling of the product is not complete) was generated in the molded product after the lot change of molding material (liquid Crystal Polymer: LCP) changed from A to B. DST-FILL compensated the process to a good product. In this case, a minor drop in viscosity characteristic of the material was seen. This was caused by a change in material from A to B material, increasing the monitor value) (i.e., holding transfer pressure). DST-FILL compensating by adjusting the barrel temperatures (i.e., the barrel temperature was increased), the viscosity characteristic of material then became equivalent to that of lot A and the monitor value (i.e., holding transfer pressure) was returned to the previous value to eliminate the short shot problem. DST-FILL is very effective for change in the mixing ratio of regrind to the molding material.

Testing shows even when molding PA66 containing regrind metering time and (shot) cushion volume were stabilized (Fig. 9). Fig. 10 shows the screw surface after the screw was drawn out after three-month of continuous molding of POM material. You can see adhesion of the molding material to the screw surface is extremely small.