Swiss CNC machining case study precision parts

Swiss CNC Project Evidence

Swiss CNC Machining Case Studies

These case studies show how SPI applies Swiss CNC machining to precision parts where geometry, burr risk, dimensional stability and inspection requirements must be controlled together. The examples focus on project evidence rather than general process theory, including small-diameter, multi-feature and long-slender components.

Each case identifies the part type, the main manufacturing risk, the controls used during production and the inspection evidence used for release. Depending on the project, that evidence may include dimensional checks, runout control, burr inspection, gauges, CMM results, FAI records or material traceability.

Case Hub Scope: This page presents selected Swiss CNC project evidence only. It does not replace our guides on process selection, tolerances, materials, burr control or first-article inspection. For machine capability, bar-size range and production services, see Swiss CNC Machining .

02 — Case Evidence Overview

What Do These Swiss CNC Case Studies Demonstrate?

This hub compares three Swiss CNC project profiles with different manufacturing risks. The overview is intentionally brief: it shows the part type, primary control focus and release evidence, while the detailed sections below explain the project-specific decisions.

Case 01

Medical Stainless Steel Project Profile

Small precision-turned component with burr, edge-condition and traceability requirements.

Control Focus

Feature condition, drawing-defined CTQs and material identity.

Evidence

Dimensional inspection, FAI documentation and lot-level records.

Case 02

Brass Connector Pin

Multi-feature brass part with threads, cross holes, slots and burr-sensitive intersections.

Control Focus

Feature completion, burr control and repeatable gauging.

Evidence

Optical review, thread and pin gauges, CMM and FAI.

Case 03

Long-Slender Stainless Steel Shaft

High L/D shaft where support, runout and dimensional stability drive the control plan.

Control Focus

Stable support, diameter control and geometric consistency.

Evidence

Air gauging, laser measurement, CMM and first-article approval.

Evidence boundary: Project-specific dimensions, tolerances and acceptance results are published only where retained records support them.
Swiss CNC machined stainless steel medical precision component

03 — Medical Stainless Steel Project Profile

Medical Stainless Steel Component: Burr, Traceability & Release Control

This project profile uses 316L stainless steel to illustrate how a small precision-turned component can require more than dimensional verification. Edge condition, burr-sensitive features, surface integrity and material traceability all need to be considered in the release plan.

Project Risk

Small edges, threads and intersecting features can retain burrs or show handling damage. Material identity must also remain linked to the inspection and lot records used for release.

Control Approach

Drawing-defined CTQs should determine the inspection plan. Burr-sensitive areas can require visual or microscope review, while dimensional features are assigned to suitable gauges or metrology.

Release Evidence

Depending on the agreed project scope, release evidence may include dimensional results, FAI records, material certification, CoC and lot-level traceability linked to the released drawing.

Evidence boundary: This section is a verified project profile, not a published dimensional case record. Batch quantity, tolerance values and acceptance results should be added only when retained project evidence supports them.
Swiss CNC machined brass connector pin with cross holes and threads

04 — Brass Connector Pin Case

Brass Connector Pin: Cross-Hole Burrs, Threads & Feature Control

This C3604 brass connector pin measured Ø10 × 35 mm and was produced in a 10,000-piece batch. External threads, knurled bands, radial cross holes and off-axis slots created a compact, burr-sensitive geometry where feature completion and edge condition had to remain consistent through production.

Project Risk

Cross holes and slots created partially hidden intersections where residual burrs could affect assembly, electrical contact or downstream handling. Threads and knurled areas also had to remain undamaged after deburring.

Control Approach

Machining and deburring were focused on defined intersections rather than general edge breaking. Tool condition and feature completion were monitored, while specified sealing or contact surfaces carried an Ra 0.8 µm finish requirement.

Inspection Evidence

Burr-sensitive areas were reviewed at 20× magnification. Thread and pin gauges supported functional checks, while CMM inspection verified selected geometry. FAI was approved before recurring production release.

Case boundary: These burr, finish and inspection requirements belong to this project and should not be treated as universal Swiss-turning specifications. For feature-specific deburring logic, see burr control in Swiss turning .
Swiss CNC machined long slender stainless steel shaft

05 — Long-Slender Shaft Case

Long-Slender Stainless Steel Shaft: Runout, Deflection & CTQ Control

This 304 stainless steel sensor and drive shaft measured Ø12 × 150 mm, giving an L/D ratio of 12.5:1 , and was produced in a 15,000-piece batch. The drawing specified a feature-specific ±0.005 mm critical diameter and 0.01 mm radial runout. The main manufacturing risk was controlling deflection, taper and runout across the long, slender geometry.

Project Risk

The high L/D geometry increased sensitivity to deflection, chatter and taper. Stable support was therefore critical as the machined length increased.

Control Approach

Sliding-headstock turning with guide-bushing support, high-pressure oil coolant, synchronized spindle feed and sub-spindle pick-up formed the machining route. Diameter and runout remained feature-specific CTQs rather than blanket tolerances.

Inspection Evidence

Diameter was checked by air gauge and laser micrometer, while CMM measurement supported runout and geometric verification. First-article approval was completed before recurring production release.

Case boundary: The ±0.005 mm diameter and 0.01 mm runout requirements apply to this shaft only. For feature-level feasibility, datum strategy and measurement planning, see Swiss CNC machining tolerances .
Inspection evidence for Swiss CNC machined precision parts

06 — Inspection Evidence

What Does the Inspection Evidence Prove?

Inspection evidence should match the CTQ being verified. A diameter, thread, runout requirement or burr-sensitive intersection may need a different measurement method. The purpose is to connect each drawing requirement to suitable, traceable evidence rather than apply one inspection method to every Swiss CNC part.

Dimensional Evidence

Air gauges, laser micrometers, pin gauges, thread gauges and CMM results can verify drawing-defined dimensions or geometric CTQs according to the feature.

Surface & Burr Evidence

Optical review can verify burr-sensitive edges, cross-hole intersections and visible feature condition where dimensional data alone is insufficient.

Traceability & Release

Material identity, lot records, inspection results and first-article documentation connect the inspected parts to the released drawing and agreed quality scope.

Evidence boundary: Inspection results demonstrate conformity for the defined features and inspected samples; they do not establish the complete FAI methodology. For that workflow, see FAI for Swiss CNC parts .

07 — Evidence Boundary

What Do These Cases Prove — and What Do They Not?

The case records and project profile above show how different geometry, materials and CTQs lead to different manufacturing and verification controls. Their value is project evidence, not a universal capability claim.

What the Cases Demonstrate

Relevant experience with long-slender shafts, multi-feature brass parts, stainless steel components and project-specific inspection evidence.

What They Do Not Guarantee

Previous results do not automatically establish feasibility, tolerance, surface finish, cost or inspection requirements for a different drawing.

Engineering rule: Every new Swiss CNC part should be reviewed against its own geometry, material, volume, CTQs and acceptance criteria before quotation or production release.

09 — Engineering Review

Have a Similar Swiss CNC Part?

Send the drawing, material, expected quantity, critical features and inspection requirements. SPI can review whether the part is suited to Swiss CNC machining, identify the main manufacturing and verification risks, and clarify what information should be agreed before quotation or production release. Previous case results are used as reference evidence, not as automatic capability guarantees for a new drawing.

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  • Material & Quantity
  • Critical Features
  • Inspection Requirements
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