Advanced RF & Microwave Development at EPIC

X-ray Inspection and Advanced Solder Process Development

Through our presence at the EPIC Centre, TWM Technology uses a Nikon XTV 160 X-ray system to inspect solder joints and connector geometry that cannot be fully examined visually.

Non-destructive X-ray inspection allows our engineers to see within an assembled component and assess features such as solder distribution, joint coverage and internal voiding. The information gathered can then be used to refine the assembly process rather than simply inspect the finished result.

Improving control of solder flow

By examining where solder has travelled within difficult-to-access joint geometries, we can develop more precise jigging and process controls. This can include using carefully selected jigging materials that expand in a controlled way when heated, helping to position, grip or temporarily seal open-ended components during soldering.

We can also use argon plasma treatment to clean and activate the metal surface before assembly. This improves surface wettability, helping molten solder flow into critical areas of the joint that would otherwise be difficult to reach.

Together, these techniques can help produce a more consistent and mechanically robust solder joint, with the grounding and electrical performance required for demanding RF and microwave applications. Better control of the joint geometry can also help minimise unwanted signal loss and reduce the risk of detuning.

Understanding and controlling solder voids

In one customer project, process restrictions meant that vacuum-assisted soldering could not be used. TWM therefore worked with the customer to develop documented acceptance criteria for solder voiding within the joint.

Using X-ray inspection, we assessed not only the size of the voids but also their position within the solder-joint geometry. This was important because a void in one area could present a greater performance or reliability risk than a similarly sized void elsewhere.

The resulting document defined:

• The maximum acceptable void sizes

• Critical areas in which voiding could lead to failure

• Locations where limited voiding could be accepted

• The inspection evidence required to assess each assembly

• Clear and repeatable acceptance criteria for future production

This collaborative approach gave the customer a practical, evidence-based method for assessing solder quality when a completely void-free process was not achievable.

From inspection to process improvement

The value of X-ray inspection extends beyond identifying defects. It allows the findings from each inspection to feed back into jig design, surface preparation, solder quantity, heating profiles and assembly methods.

By combining X-ray analysis at EPIC with TWM’s machining, plating and specialist assembly capabilities, we can support customers throughout process development—from investigating an internal joint to establishing a controlled and repeatable production method.