The trend toward increasing numbers of cavities in hot runner systems requires that every millimetre be used effectively. By reducing the diameter of the hotspring connection head by about 30%—from 6.9 mm to 4.8 mm—with the hotspring 1.8 x 3.2, Hotset offers engineers a further option in fulfilling the new requirements.

Similarly, the space needed for the connection head of the hotspring/Mini 1.3 x 3.2 is only half of the former requirement. The previously bifilar coiled heating element can now be produced with one connection head, thus offering a back-up option for thermal stability in the smallest space. With this new single-connection-head element, Hotset offers designers the possibility of using an extra heating element as a spare or as a booster for doubling performance within a given installation area.

The hotspring spike-system is a reflection tube that, by simple twisting along its full length, can be adjusted perfectly to the tool to be heated, ensuring optimal heat transfer and increasing the maximum sheath surface load to 10 W/cm2. Featuring tool-diameter tolerances of several tenths of a millimetre, the system provides a permanent strong fit.

The hotspring spike-system covers a wide range of requirements for small designs with tools having diameters as small as 10 mm and clamping element lengths as short as 40 mm. In addition, the system can be used for clamping hotspring heating elements with larger dimensions.

Hotset’s hotrod heating elements offer other application advantages in addition to even, precise tempering and differential heating of various temperature zones. One involves maintenance—specifically, refitting. The hotrod elements can be mounted and demounted several times, and are extremely rugged. If during the masterbatch or compounding process, for example, a fast refitting of the machine is necessary, the benefit of using angled hotrod elements for extrusion heating becomes apparent.

Based on proven hotslot technology, the FIT system extrapolates existing heating technology for such plastics applications as the nozzle-heating of hot runner systems to new levels to provide unforeseen advantages for the user. The hotslot-FIT system fixes itself tightly, but it is not a true clamping mechanism: no clamping mechanism per se could match the FIT system’s tripping energy of 24 kN at a nozzle temperature of 500°C (and, at 300°C, a remarkable 10.5 kN). Obviously, the hotslot-FIT system will improve heat conduction in plastics processing when it clamps that tightly at the optimum temperature level.

Hotslot-FIT system technology provides further advantages. The wattage distribution is individually specified as the heating element is inserted into a specially designed slot, cutout, or hole. For example, the wattage can be distributed to the nozzle tip.

In addition, owing to the design of the self-clamping system, the wall thickness of the heating elements can be maximally reduced. Front installation and removal of the heating element also are simplified, because the clamping action relaxes for release when the heater cools down.

A critical component of production equipment is the heating element that could be a potential source of ignition. With the explosion protection afforded by its hotrod® heating elements, Hotset Heizpatronen und Zubehör GmbH provides an answer to the needs of manufacturers who are subject to the upcoming guideline.

Manufacturers who process powdery or powder-generating materials especially have to establish special safety precautions according to ATEX. Their own problem can in some cases be solved only by their machine suppliers, including those whose machines will be used in areas only infrequently or temporarily dusty, such as packaging areas. The manufacturer has to meet the ATEX guideline throughout the production process.

The hotrod distributes constant heat over its whole length, with an increase of wattage to the ends, and is therefore advantageous for such packaging applications as weld-sealing plastic bags. The wattage distribution is repeatable, so it can be used also in seals and cutoff knives. The hotrod offers PTB-certified explosion protection in all these applications, as well as humidity protection to IP67. Thus, its incorporation into production machinery prepares the machine OEM for the ATEX guideline.

The explosion protection afforded by Hotset’s new heater will become even more important in the future, as more and more countries are announcing their intention to implement the ATEX guideline through their own national regulations. Examples are Switzerland and the USA, which have enacted laws identical to ATEX.

In addition to the control element, the complete standard functional range of these controllers includes ramp and automatic ramp functions, further absolute or interrelated set values, an automatic thermal break, and a flexible parameter-specific timer function. The flexible 85- to 250-V AC power supply lets the devices be used in machines that will be exported.

Analogue and digital inputs and digital outputs are present, and data interfaces support such additional functions as CAN-bus communication. All adjustments, status indications, and so on are clearly presented in the display. New-generation hot-control controllers also provide alarm monitoring of temperature and heat current and of the actuator in the heating circuit.

The hot-control C 248 and C 296 are technically advanced, high-function temperature controllers that have been specially designed for the application fields served by Hotset heating elements. They feature an attractive price-to-performance ratio that is made more alluring during the product introduction period, which runs through June 30, by virtue of a 5% discount on each order.

Although the hotslot-FIT system fixes itself tightly, it is not a clamping mechanism in the truest sense; it would be impossible for an ordinary clamping mechanism to accommodate the FITsystem's tripping energy of 24 kN at the nozzle temperature of 500°C (and 10.5 kN at 300°C). Clamping that tightly at the optimum temperature level, the hotslot-FIT system will obviously improve heat conduction for plastics processing significantly.

Owing to the self-clamping nature of the system, the wall thickness of the heating elements can be reduced considerably. Front-installation and removal of the heating element is simple: the clamping loosens when the heater cools down.

Another advantage provided by hotslot-FIT system technology is the possibility of individually specifying the wattage distribution for a heating element inserted into a specially designed slot or cut-out or hole. The wattage can, for example, be directed precisely to the nozzle tip.

Hotset has developed a high level of innovative ingenuity with respect to the technology of heating hot runner systems. The hotslot-FIT system is the company's latest offering to hot runner suppliers seeking to stay ahead of competitors. Because the hotslot technology has been employed successfully in hot runner systems for some years, solid production know-how enables Hotset to deliver these heating elements instantly.

With its introduction of the hotslot-FIT system, the manufacturer underscores the high research and development standard it maintains to meet the special demands of the hot runner industry.

These changes have in turn forced manufacturers of mould heating elements to improve their products. Ordinary cartridge-type heating elements take a lot of space, heat transfer to the tool is spotty, and the process engineering is difficult because the plastic has to be kept at a consistent temperature.

Tubular heaters maintain this temperature consistency, but, with ordinary heaters of this type, stock-keeping and replacement are difficult, as are handling and installation. In addition, these heaters are already bent to fit the milled groove, so they place restrictions on tool construction.

Then the heating element manufacturer Hotset Heizpatronen und Zubehör GmbH had the innovative idea to create the hotflex^® flexible tubular heating element to stay abreast of the changes. The three-dimensionally bendable hotflex represented a quantum leap for industrial heating and especially for the construction of mould tools. It considerably simplified design and handling in heating mould outlines and gave users freedom to make production and tool modifications. Other advantages of the hotflex heater are low maintenance sensitivity, shorter tool downtime, high energy savings, easy stocking of replacements, and, of course, accommodation of the shrinking-tool trend.

This tubular heater can be manually bent and easily pressed or inserted into a milled groove by means of, for example, a plastic hammer. Its special surface makes additional casting unnecessary. The hotflex has a robust yet flexible stainless-steel sheath and connections at both sides. The sealed sheath ensures high resistance against corrosion by liquid or powdery foreign material. Its robustness contributes to the heater's high production reliability and long lifetime.

With a diameter of 6.5 mm resp. the 8.5-mm version (or 8.2 resp. the 8.0-mm version also available), the hotflex is supplied in a straight form with a voltage of 230 V. Several dimensions with different wattages are stocked and ready for delivery. In addition, Hotset offers the hotflex with a square profile of 6 x 6 or 8 x 8 mm. A surface load of 15 W/cm² can be realized for lengths of 250 to 2600 mm.

The hotflex heater comes equipped with numerous connection options. Among the possibilities are M2.5- or M4-thread pins, flat plugs, insulated or blank lathe-cut leads, and the plug-and-heat ceramic clamp.

A scientific study recently conducted by the Märkische Fachhochschule, a technical college in Iserlohn, Germany, showed that hotflex could restrict temperature variation to 1.3°C (as opposed to 12°C with a traditional heating method) in a tested Duroplast-forming application. And another study found that the Hotset technology ensured consistent temperature, higher and faster cross-linking of the material, and a reduced cycle time.

The new three-dimensionally bendable heater can be flexed manually and easily pressed or inserted into a milled groove. It is unnecessary to cast the element in place. Advantages of its design include smaller tool dimensioning, shorter downtimes, low maintenance sensitivity, and high energy savings. Users also benefit by having greater flexibility in making production and tool modifications.

The hotflex tubular heater has a flexible stainless-steel sheath and connections at both sides. The robust sealed sheath ensures resistance against corrosion. This feature and its laboratory-proven thermal protection make the hotflex a guarantor of long life and high reliability for working production systems.

Laboratory testing bears this out. In one duroplast moulding operation conducted as a test, the heater kept temperature differences at 1.3°C versus 12°C with a common heating method, and it reduced the cycle time.

Available in versions with diameters of 6.5 and 8.5 mm, the hotflex heater can be supplied from stock in several dimensions and with an operating voltage of 230 V. Depending on the version, a surface load of 15 W/cm2 is easily achieved for lengths of 250 to 2,600 mm. Flexibility extends to the choice of connections. Options include M2.5 or M4 threaded pins, flat plugs, lathe-cut leads, and a plug-and-play ceramic clamp.

The hotslight® microheater, based on the proven hotslot® principle, is a coil heater pressed into a slot on a brass or stainless-steel turning part or carrier plate. The slot can be chosen according to the desired power distribution available within a minimum bending radius of 3 mm. This produces optimal temperature control. The robust carrier material can be furnished with special holes or cutouts. The space-saving hotslight can have a minimum wall thickness of 1 mm along the total heating element. It provides reliable point heating with a maximum surface load of 10 W/cm2 at flexible connection voltage.

Intended to supplement Hotset's range of round and flat tubular heaters, the square tubular heating element with a standard 6 x 6-mm profile and stainless-steel sheath is stocked in various dimensions. It is fixed by force fitting, thus facilitating mounting and demounting.

Finally, Hotset's new generation of WRP-series square, flat, and round coil heaters is supplied with a humidity-resistant connection side rated to IP65. Designed not to lose humidity protection with wear, this innovation increases production safety by minimizing failures due to ambient humidity.

Featuring a flexible stainless-steel sheath and connections at both sides, and with a minimum internal bending radius of 10 mm, the tubular heater can be bent and easily pressed or inserted into a milled groove. Connection options are M2.5 or M4 thread pins, flat plugs, glass-silk-insulated leads or blank leads, and ceramic clamps.

The helical coil cartridges are high-compression heating elements and offer high performance with minimal space. The integrated thermo element is a completely plastic-impermeable (and thus production-safe) unit. The application-specific performance distributions are reproducible and therefore allow the easy exchange of heating elements without further adjustments, reducing set-up times.

The helical coil cartridges are especially suited for heating extrusion heads in constricted spaces with high technical demands regarding temperature guides and control.

Although the minimum thickness of the carrying material has to be just two millimetres, the position and options of the exit can be chosen. When using brass plates as the carrying material, flat heatings with a heating temperature of 650 degrees Celsius maximum can be achieved. The surface load is up to 15 W/cm2.