Custom Machining and CNC Routing Services from Allplastics

Antenna Mount Precision Machined & Assembled

Allplastics Engineering completed an intricate design project to disassemble, manufacture and reassemble an antenna for the National Measurement Institute. The aim of the project was to eliminate all the slack in the connections and to minimise the movement of the arm when it is rotating. A lot of parts had to be custom machined & CNC routed from Bakelite and all materials needed to be from plastic so there is no radio wave interferences to make the antenna slide & work smoothly.

Acetal sleeve pads were mounted inside the sleeve with custom made M5 Plastic Screws. The Acetal pads minimizes the lateral movement of the sleeve on the post, it only allows the sleeve to move up and down. PTFE strips were glued on the post to make sure that the sleeve slides smoothly. The advantage of using PTFE strips is that it will give a low coefficient of friction between post and sleeve.

Rigid Bakelite (Tufnol) Pads were incorporated in the assembly.
The National Measurement Institute were extremely impressed with the service and outcome from the project.
Brief: The dummy arm section 50 x 50 will be inserted in the rotating bearing. A laser pen will be clamped on the end of the dummy arm on the rotation axis. Deviation of the laser from 0 to 90 degree will be checked. Once the alignment is done, the real GRP arm will be fitted and a dummy inner arm will be fitted inside the GRP arm to check laser deviation for the second antenna configuration.

• Design and provide new Bush for rotating mechanism
• Design and provide dummy arm with a laser pen clamp on its end
• Design and provide dummy inner arm sleeve with a laser pen clamp on its end.