Hot Runners: Family Mold Friendly Systems, Cylinders, Nozzles and Cooling Tech Featured
At K 2019, HRS’ FLEXflow will power a pair of family molds and the company will showcase new cylinders, hot runner nozzles and cooling technology.
HRSflow will use servo-driven valve-gate technology to independently control stroke, timing and force of each individual pin in family molds at K, showcasing how its FLEXflow system can overcome differences in part weights, volume and wall thicknesses.
HRSflow will mold upper and lower bumper parts in one shot. Made from a 14%-talc-filled polypropylene (PP), the two components have volumes of 3333 cm³ and 2170 cm³, respectively. The company says FLEXflow results in surfaces without any flow marks and accurate control of deflection on each component. The tool at show is equipped with a 21-nozzle servi-driven valve gate hot runner, including two angled nozzles.
A second family mold will create three PP car interior door module components, with volumes of 560, 338 and 58 cm³. Wall thickness range from 2.3 to 3 mm, with a cycle time of 55 seconds. This mold features an eight nozzle, servo-driven valve gate hot runner, designed for sequential injection molding. Both hot runners are equipped with the new FLEXflow one-manifold servo-driven valve-gate cylinders.
Cylinder Range Extended
HRSflow will also showcase its recently extended portfolio of compact cylinders that require limited installation space. This includes a series of pneumatic cylinders that can be installed without removing the hot runner from the mold plate. Featuring good thermal insulation, the cylinders do not require cooling for a wide range of polymers. The modular design reduces the number of parts and maintenance, and the cylinders are available with or without end stroke; in a damped version; or with end stroke and pressure sensor.
In addition, compact hydraulic cylinders that require only small cut-outs in the tool and minimize heat transfer from the manifold will be featured. In addition to the basic design, a dampened version is available. Further variants offer a microswitch for end-position detection as well as an adjustable version to compensate the position of the needle by ±1 mm without mechanical reworking.
Small Nozzles for Low Shot Weights; Water Cooling Eliminated
HRSflow will also present the SA Series, which is its smallest series of screwed-in hot runner nozzles for very low shot weights. They feature a compact cut-out and promise optimal thermal conditions for flexibility in processing engineering polymers, including materials with high fiber loadings or high viscosities.
The company will also display its HRScool technology, which it says can eliminate water cooling for the most common automotive applications. The design minimizes heat transfer from the hot tool plate to the cylinder, while a highly thermally conductive cover maximizes heat dissipation from the cylinder to the cold clamping plate.
There are simple explanations for the most common hot-runner problems and equally simple ways to prevent them. One is to take advantage of features often overlooked in today’s hot-runner controls.
Last month, we discussed the general issues of an organized and disciplined process of troubleshooting and correcting mold defects.
Get the sprue, runner and gate sizes close to ideal the first time around.