Planning a PTFE Drilling Trial Around the As-Drilled Hole Wall

A drilling trial for a PTFE laminate should include examination of the hole before later treatment obscures its condition. Starting only with the finished plated hole makes it harder to distinguish the original machining result from subsequent processing. Select and preserve intermediate samples deliberately.

Record the exact drilling construction

Rogers’ RT/duroid fabrication notes emphasize preventing connected smear during drilling rather than assuming it can readily be removed later. This material-specific limitation supports a trial focused on the as-drilled state, without prescribing the same parameters for all PTFE composites.

Identify the laminate grade, layer arrangement, stack position, entry and backup material, tool model and tool-use history. Retain the drilling program version and actual production setup used for the sample.

Choose samples that answer the process question

Keep the comparisons controlled. If the tool, stack height and material grade all change, document that the trial evaluates a combined route rather than attributing the result to a single factor.

Describe the hole-wall observation precisely

Use suitable preparation and examination to identify the condition of concern. Record where it occurs along the hole and whether it is associated with a particular material interface. Avoid treating every dark region in a section image as the same defect.

For example, if a questionable feature appears mainly in one position of a drilled stack, retain that position in the report. Combining images under one panel identifier can erase the comparison needed to understand the result.

Validate the downstream connection

1. Review the as-drilled samples against the agreed criterion.
2. Process matched material through the approved treatment route.
3. Inspect the completed plated holes.
4. Include the required reliability or electrical examinations.
5. Set the released drilling boundary from the combined evidence.

A visually acceptable entry opening does not establish the condition throughout the hole. Likewise, a satisfactory result from a new tool does not define an unrestricted tool-use interval.

Keep original rejected examples when they are useful for future process monitoring. Identify their actual cause only after the investigation supports it.

State whether the selected tool-use point refers to holes, accumulated drilling distance or another controlled quantity. Combining records that use different definitions can make two tools appear equally used even though their documented exposure is not directly comparable.

The entry and backup trial guide covers support materials, and activation-route review connects the drilled surface to metallization.