Automatic thermal treatment plant

Automatic thermal treatment plant

Specialised conveyor furnaces: Conveyor-chamber furnaces

The principle of a conveyor furnace can be transferred to different applications. The advantage lies, among other things, in the fact that several successively activated application processes can run in a fully automated mode in separate chambers.

Conveyor-chamber furnaces for the automotive industry

This conveyor furnace has been designed for tempering aluminium pistons for the automotive industry. The plant works fully automatically except for the loading and offloading of the transport cages. After the thermal treatment in the furnace the components are transferred from the furnace into the water quenching bath within 20 seconds. The immersion depth can be adjusted infinitely in the 1 mm range in the thermal treatment programme. The temperature regularity - measured in terms of the input material at the end of the hold time - is < ± 3 K. The whole process in the conveyor furnace is controlled by a higher-level control system so that batch tracking and the preparation of batch protocols are possible.

Gelling and cooling with the conveyor furnace

Displayed here is an electrically heated plant for gelling and cooling, which seals the welding seams of car doors. The batch rack is placed on the transporting device with its own bogie. A special cycle drive then grabs the pallet and transports it into the first furnace chamber. After completing the thermal treatment, the object is automatically transported to the cooling chamber. At the same time, the next batch is retracted into the heated chamber.

Conveyor chamber furnace as a powder-nitriding plant

This fully automatic furnace is suitable for powder-nitriding. The batch rack standing on basic cast grating with a maximum weight of 250 kg is pushed through the plant. To minimize the oxygen content in the conveyor furnace the pallets are put into vacuum sluices at the furnace entrance and at the cooling chamber exit . After the thermal treatment of the input material in the furnace with a maximum furnace room temperature of 950° °C, the pallets are then transferred directly into the cooling chamber. The material is cooled there to a temperature below 300 °C. There is a storage section in front of and behind the plant to ensure continuity of the processing.

Chain conveyor furnaces for special tasks

Conveyor furnaces are often the most economical solution for the thermal treatment of series products. Gas or electrically heated conveyor plants are used.

Conveyor furnaces for soft annealing of forged components

The adjacent plant was designed for the purpose of soft annealing of forged components (0.04 - 0.6 kg/piece). The throughput is 3500 kg/h and the maximum furnace room temperature is 750 °C. The usable space was set at 1300 x 6480 x 120 mm (width x length x height). From the forging heat, the input material is transported to the conveyor furnace via feed belts and vibrating conveyors. Four control areas which heat or cool in accordance with the requirements ensure that thermal treatment takes place according to the programme. The use of high speed burners/cooling jets permits intensive transmission of heat.

Special furnace for the ageing of clutch springs

The conveyor furnace is designed for the ageing of clutch springs which are placed on crooked supporting pieces. The processing temperature was set to 250-300 °C. The furnace is operated in cycles. The maximum cycle time is 30 seconds. The cycle length is adjustable and can be 80-240 mm. The transport mechanism consists of a two-strand roller conveyor chain, between which the pick-up device for the springs was fastened. The maximum gross batch mass is 1.5 kg/80 mm. To keep the temperature in the furnace room uniform, there is a circulation fan in the ceiling of every furnace area . There is one pneumatic lifting door at the furnace entrance and exit respectively, and this opens at the stroke of every cycle so that only one spring comes to a stop in the pick-up position at any one time. This is then led to the next production process by a pick-up robot (not part of this plant). The transport system is controlled using an electromotor which is equipped with an incremental encoder for positioning.

Thermal treatment of forged components - with belt conveyor furnaces

The belt conveyor furnace is for thermal treatment of forged components with a maximum diameter of 50 mm which are conveyed directly to the furnace after the forging process with a temperature of approx. 500-600 °C. The maximum operating temperature in the furnace was set to 780 °C. The forged components are conveyed to the furnace through a chute found at the entrance. After passing through the heating and holding zones, the components again exit the industrial furnace through a chute. The plant is designed for an output of 600 kg/h. Lateral boards on the cast link belt prevent the input materials from falling off the transport route. The maximum loading height of the belt is 50 mm. The dimensions of the transport route are 800 x 3400 mm (width x length). The furnace is subdivided into three heating zones across the transport route, with the first zone equipped with an air circulation fan. This serves to keep the temperature of the input materials moderate. The second and third heating zones are designed as holding zones. The drive system for the belt propulsion roller is located on the furnace ceiling due to lack of space.

Industrial furnaces according to customer wishes: Conveyor slot furnaces

Sintering of nickel powder on metal - with a conveyor furnace

This plant was manufactured for sintering nickel powder on a thin metal fabric. The prepared input material (2000 x 2000 mm) is pushed through an overhead track into the furnace and then centred. After closing all doors and hatches, the thermal treatment process then takes place at 1000 °C. During this process, air which is distributed over the entire floor is constantly blown into the furnace to ensure a sufficient oxidation. The electrical heating device (a heating coil on supporting pipes) is subdivided into twelve zones. These are trimmed to such a precise extent that the value of -/+2 K is not exceeded in the entire furnace room. For servicing purposes the furnace can be opened up completely.