A 3D Printed 10N Deadweight Machine

A 3D Printed 10N Deadweight Machine A deadweight machine is a mechanical system designed to apply a known force onto a load cell using calibrated weights. The process involves applying the calibrated weights to a load cell in evenly spaced increments. This allows the calibration technician to determine the characteristics of the load cell, such as hysteresis and linearity, as well as attribute the mV/V values produced by the load cell at each increment to a known load. At Interface, we decided to build a 10N deadweight machine to be used for calibrations and as a working scale model as part of the design and potential manufacture of a larger 100kN deadweight machine. Using CAD and 3D printing as our chosen method of rapid prototyping, we built a 70cm tall machine for both tension and compression calibrations. This machine consists of 10x 1N weights and nearly 70 individual parts. A motorised lead screw is used to lift two moving mechanisms that hold the load cell. The arrangement of these parts depends on if the load cell is in tension or compression. In order to 3D print the weights, but still achieve an accurate weight of 1N, we decided to design the weights to be hollow which allowed for a brass mass to be inserted. This meant that any inaccuracies in the 3D printed parts, and thus the mass of each weight, can be accounted for by reducing the mass of the brass inserts. This ensures that each 1N weight is as accurate as possible to guarantee a high-quality calibration. Our aim is to achieve an uncertainty of applied force of +/-0.02% so we have the ability to work to a Class 0.5 per ISO-376. Using rapid prototyping to produce the parts for the machine meant that there was a lot of assemblies to be done. During the process of assembly, small adjustments were made to ensure that the part fit together securely and keep the machine sturdy. Ease of assembly and disassembly was a large consideration in the design process. Despite being made up of nearly 70 parts, the machine can be disassembled in minutes making it easily mobile and easy to pack away. Overall, this 10N machine offers a lot to us at Interface. Not only does it offer us the ability to do highly accurate calibrations, but it also acts as an opportunity to find flaws in the design and improve them for further iterations and larger-scale machines.

For more information on A 3D Printed 10N Deadweight Machine talk to Interface Force Measurements Ltd