Research On Temperature Control System Of The Fused Deposition Modeling For Spray Head

Fused Deposition Modeling is one of the most widely used Rapid Prototyping Technique all over the world, which plays an important role in the product design and evaluation, function test and product showing, etc. In recent years FDM has been developing very quickly in China, but its technology used is far from advanced ones in foreign countries. Spray head is very important part of this system, because it makes great effect on improvement of stability, efficiency and precision of the FDM. Spray head is heated to fused filament. The temperature should be reliable and precise, or it would aspect speed of spraying. So this paper introduces a method to control temperature.Temperature controller of FDM is used to regulate the temperature to a setting point by changing average voltage of load through Silicon Bidirectional Thyristor. The hardware of temp-controller is composed of keypad circuit, LCD module, Acquisition circuit, MCU-51 and Actuator. Fist, temperature sensor can convert temperature signal to electrical voltage, then A/D conversion that accepts voltage signal changes analog into digital signal. MCU read the digital output from converter chip through parallel interface. MCU process the data according to PID law. MCU writes the result to D/A conversion to control Actuator. Keypad for setting the parameter of controller, LCD module displays the output data.The Software of this system can be divided into 4 parts: acquisition task, processing task, key ISR and communication handle. In order to manage the tasks effectually and share public variable without dangerous,μC/OS -Ⅱembedded operation system schedules them and provides synchronization methods solutions to race conditions. In addition, this system can communicate with PC. Parameter is also displayed and set by it.The new tem-controller will improve the precision of temperature and product.