SILICONE RUBBER HEATERS PRE-HEAT NYLON POWDER CART

A customer in the 3D printing industry approached us in need of a heating solution for a complicated process:

A large amount of Nylon powder (around 40 kg) inside of a cart needed to be heated.
The material is loaded onto a bed.
The bed is then slowly lowered into the cart. As the bed is lowered, more Nylon powder is deposited and heat needed to be consistently applied to the Nylon powder.
It was crucial for the temperature to be maintained at around 150° C.

diagram of nylon powder cart being heated

Due to the three-dimensional shape of the cart, custom silicone rubber heaters needed to be designed for the top, sides and bottom of the assembly - three custom designs in total.

The top heater was designed with very large unheated margins. This was done as the top portion of the cart was very large, yet the customer only needed heat applied over the small portion that made contact with the nylon powder. On this top heater, a unique lead termination style was utilized known as a “patch channel”. This channel of silicone encompassed all power leads and sensor leads as well.
The side heater was designed to be narrow and long, so that it would wrap around all four sides of the cart.
The bottom heater contained eight mounting holes at each corner and edge of the heater. The heating element was able to be effectively routed around these holes, ensuring that sufficient heat still be applied around these mounting holes.

The heaters worked seamlessly with the process. As the Nylon powder is deposited, the side and bottom silicone heaters are under operation. When the bed reaches its final depth, the top heater is placed, allowing additional heating of the powder if necessary. RTDs were integrated into each heater design for precise control of each heater. The RTDs were incorporated near the lead exit so that only one bundle of leads from one location exited each heater. The carts are able to be pre-heated to the desired temperature, and afterwards the carts roll into the printing machine for curing of the nylon.

The three custom designs allow for optimal heating in this situation. The flexible nature of the silicone rubber heaters allows them to conform nicely to the sides of the cart and transfer heat effectively. The customer is able to mount these heaters to one of the powder carts and operate them independently as they please.