Renishaw

gets better fit and impedance control for complex flexible PCBs in metrology instruments using CR-8000

Flexible and flexi-rigid PCBs are integral components within many of Renishaw’s products, and detailed signal integrity analysis is needed to ensure high speed digital signals can be transmitted with minimal distortion. Renishaw migrated to Design Gateway and Design Force, part of Zuken’s CR-8000 PCB design suite, primarily to help with the design and analysis of next-generation flexible PCBs.

Working in 3D for the first time, Renishaw’s PCB designers noticed a host of benefits, including fixing housing fit issues upfront and easier component placement. They also boosted their controlled impedance routing for high frequency signals using electromagnetic field solvers in Design Force. Working in 3D has enhanced collaborative engineering within Renishaw.

Results

Fit is fixed early in the design flow

Design Force offers easier controlled impedance routing for high frequency signals using electromagnetic field solvers.

Controlled impedance routing is a prerequisite for good digital circuit signal integrity, and signals – particularly high frequency ones – require constant characteristic impedance from driver to receiver. Renishaw uses Zuken’s CR-8000 suite for controlling impedance. Constraint Manager is used to specify the limits of characteristic impedance and Lightning is used to create impedance templates. This allows them to select a group of nets, using a net class, and then use the field solver to automatically calculate the impedance specified – adjusting the track widths to match.

Improved layout with 3D placement

A major benefit of the migration to CR-8000 is that Renishaw’s PCB designers have the ability to visualize and manipulate board designs in 3D.

Pete Leonard, Electronic Design Manager for Group Engineering, Renishaw, comments: “We can place components in a 3D environment, taking into account any constraints that may have come over from our mechanical engineers and then switch back to 2D for routing.

Design tested using 'what if' scenarios

What if’ scenarios can be viewed by bending the flexible PCB.

During the design of the flexible PCB, Renishaw’s PCB designers created a user-defined layer called ‘BendLine’ (a case- sensitive reserved name). On this BendLine layer, polylines were drawn to represent the axes around which the flexible PCB needs to bend. Properties such as bend direction, angle and radius were then applied to each of the polylines. Renishaw’s PCB designers were then able to move components around in this 3D environment. They were also able to import (via .stp file) the housing around which the flexible PCB must bend.

Renishaw discuss their relationship with Zuken

Play 2:59 Play 3:31 Play 3:19

Our use of Design Gateway and Design Force within Zuken’s CR-8000 platform has enhanced the way our PCB designers and mechanical design engineers work together when developing complex flexible and flexi-rigid PCBs.

Pete Leonard, Electronic Design Manager for Group Engineering at Renishaw

How Zuken have helped Renishaw

Download the full case study
 
Visit the Renishaw website

Discuss your design issues with our experts

We can help you craft the best solution for your company’s specific requirements
Get in touch