Case study

Challenge

• Medical customer who had very specific requirements on quality and product performance.
• They wanted to add haptic feedback to their ‘medical dummies’, to simulate the feeling of a patient’s heartbeat.
• They were seeking a reliable manufacturing partner with rigorous design, validation, testing and quality procedures.
• Precision Microdrives was asked to progress a prototype design using a custom vibration motor, and prepare the design for mass production.

Solution

• A bespoke vibration motor with a custom winding tuned to operate at a specific speed (frequency).
• Provided the necessary torque to reach operating speed for an unusually large eccentric mass within 400mS.
• A CNC machined brass weight and aluminum enclosure with internal harmonics dampening.
• PCB backpack and wireset, that contained very high performance EMI / EMC filters, to prevent disruption to medical equipment in a hospital environment.

Results

• Powerful and realistic patient simulation now adopted world-wide.
• Successfully managed our client’s risk with verified and reliable technology.
• Carefully optimised for in-house manufacturing by in-house design-for-manufacturing teams.
• Carton packing arrangement designed to optimise air freight shipping charges.

STAGE 1

Designing for application

• We designed the vibration motor with a custom winding to provide the necessary torque to drive the unusually large eccentric mass.
• To generate the vibration G-forces for an accurate heartbeat simulation we optimised the motor windings and mass weight, which was then CNC machined in brass.
• We added a PCB backpack for the motor onto which the high performance EMI filters were fitted.
• The customer mapped out the envelope of the vibrating assembly so it could fit into the end product.

STAGE 2

Technical specifications

• The enclosure was machined from aluminium alloy, with a carefully designed set of hooks to locate the assembly into the final application.
• The split enclosure is held together by an integrated thread and IP67 sealed, with a silicon washer and suitable tightening torque.
• The thread was introduced as part of the design for manufacture process making manufacturing more efficient and consistent.

STAGE 3

Precision manufacturing

• We manufactured a large number of jigs and fixtures to aid assembly on our lines. We also built an end of line tester to ensure the vibration frequency and amplitude was optimal.
• We understood our customer’s challenges and provided an effective solution to a very high standard, whilst reducing their risk.
• We optimised the shipping for the customer, before they asked, by designing a carton packing arrangement suitable for air freight.