Daniel Doerrfeld Mechanical design engineer @

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Pneumatic tube-and-fitting assembly station for a medical customer

Assemblies and machines, Fixtures and tooling, Drawings and GD&T, ’26 — Primary designer

Benchtop assembly station with a black anodized base, a hinged tool plate held open on two gas springs, two fitting clamps on the plate, a central press cylinder, and a green start button
Role
Primary designer
Year
2026
Tools
Autodesk Inventor 2025
Materials
Stainless steelBlack anodized aluminumMarkforged Onyx
Processes
CNC millingWire EDMJig grindingAnodizingFDM printing

Overview

A benchtop pneumatic station that clamps, locates, and presses tubing onto round-body fittings for a medical customer, designed in Inventor.

Problem

Joining tubing to round-body fittings by hand is not repeatable, and it keeps the operator’s fingers at the joint during the press.

A medical customer needed the joint made the same way every time. Assembled by hand, seating depth and alignment depend on the operator’s grip and push, and every press happens with a hand next to the fitting.

The station had to hold both halves of each joint in known positions, apply the press stroke pneumatically, keep hands clear while it does, and fit on a bench with shop air as its only utility. Tooling in contact with the parts had to be corrosion resistant and easy to clean.

Approach

Every part-contact surface lives on the tooling, and every force comes from the pneumatics.

A hinged tool plate carries two spring-loaded fitting clamps; it swings open on gas springs for loading and closes against a pivot bar that sets its position. Below it, the fittings sit in machined nests on a slide carriage, and a pneumatic cylinder drives the press stroke once the plate is closed and the start button is pressed.

Materials follow the job of each part. Nests and clamp details that touch product are stainless steel. The base, tool plate, and structural brackets are black anodized aluminum. Guides and covers with shape but little load are printed in Markforged Onyx, which kept lead time and cost down on parts that would otherwise be five-axis work.

The nests are detailed for inspection as much as for machining. Locating features are dimensioned from a common datum, dowel bores carry a 0.001 inch band, the counterbores are called out to be cut after the wire EDM operation so the ground surfaces are not disturbed, and the fitting relief is defined by angle and depth rather than by a profile that would have needed a CMM program to verify.

The pneumatic valve and plumbing are mounted inside the base with a cutout for service access, so the working surface stays clear and the station can be wiped down.

Interactive model

Complete assembly station with the tool plate open, showing the fitting clamps, the nests on the slide carriage, the press cylinder, and the enclosed base
3.0 Complete assembly station with the tool plate open, showing the fitting clamps, the nests on the slide carriage, the press cylinder, and the enclosed base. Loading the interactive model downloads about 2664 KB. Model

Drawings

Previews are sanitized. Select a drawing to enlarge it.

  • Detail drawing of the round-body fitting nest with front, top, side, and section views, hole callouts, a 32 degree relief, and a title block
    4.0 Nest for the round-body fitting. Dowel bores are held to a 0.001 in band and the counterbores are cut after the wire EDM operation. Customer and job identifiers are redacted. Drawing

Outcome

Metric Result
Status Designed and released, 2026
Modeled components 101

The station was designed and released in 2026 as a complete model of 101 components, with production drawings for the machined tooling.