PID control box houses the PID controller, Fotek Solid State Relay (SSR), round toggle switch and computer power cord plugin in the back.
Print the two parts separately to minimize delamination.
Filament extruder temperature controller used for extrusion heads that are coupled with direct drive, worm drive, or belt driven motors.... more to come soon.

[Thanks Zen for the push].

These PID controllers are commonly used in kiln control boxes for standardizing firing temperatures. The PID box will then require a metal case for to reasons high temperatures and radio frequency [RF] noise generated by the the kiln power turning on/off can effect the PID portion of the controller.

Print the two parts separately to minimize delamination.
Be sure to check PID face mount dimensions (in millimeters) manufactures have 2-5mm variances. The relay mount works for the standard cheap Fotek Solid State Relay (SSR). The relay in the photo is not the standard SSR but has ~ same hole spacing.
Parts for the assembly cost ~ $60 for PID, SSR, and toggle switch. You can get the toggle from Radioshack [they no longer exist] vetco, or local hardware/hobby store. I pulled the cord plugin off of the back of a dead computer power supply. [it makes the control box easy to move around]. PID and SSR are cheapest online.
Remember the SSR shouldn't be more the 20 amps otherwise it will trip your break rather then run the PID.
More information… Warning/Disclaimer
Generally you want ~ 100-50 ohms for safety.
V=IR …right so [120 Volts of AC]/ [6 ohms] => draws 20 amps of current… however if you using straight nichrome for your resistor lets just say you will hit the glowy glowy point before the circuit breaker will trip. This means it will catch fire immediately. And I do mean immediately.