Cold Plate Manufacturing: Press-Fit vs Epoxy Resin

01 — What is the problem?

Tube-laminated cold plates are produced by inserting metallic tubes into machined grooves on an aluminium plate. Two main processes exist to secure the tube and ensure thermal contact: mechanical press-fit (tube mechanically deformed into the groove) or epoxy resin lamination (thermally conductive epoxy fills the gap between tube and groove). Both methods aim at minimizing thermal resistance between the fluid and the plate, but they differ in material compatibility, manufacturing constraints, and long-term contamination risks.

02 — Why does it happen?

• Cold plates need a reliable thermal interface between the tube and the aluminium body to transfer heat efficiently
• Mechanical, optical, and contamination-sensitive applications (medical, semiconductor, optics, defense) require choosing the right process
• Tube material (copper vs stainless steel) drives the manufacturing process: copper is ductile enough to be plastically deformed, stainless steel is not
• Production cost, tooling availability, and cleanliness requirements differ significantly between the two processes

03 — Consequences

• Choosing epoxy resin in a contamination-sensitive environment can introduce outgassing or particulate pollution over time
• Trying to press-fit stainless steel tubes leads to poor mechanical contact, deformation of the plate, or tube cracking
• Inadequate process selection can compromise long-term thermal performance through gap formation or resin aging
• Incompatible tube/plate combinations can cause galvanic corrosion if not properly isolated

04 — Common mistakes

• ✗Specifying press-fit for stainless steel tubes — only copper tubes (ductile) can be mechanically pressed into aluminium grooves
• ✗Using epoxy resin in clean room, vacuum, or optical environments without considering outgassing risk
• ✗Assuming one process delivers better thermal performance than the other — in practice, both are equivalent when properly executed
• ✗Ignoring the curing time and temperature constraints required for epoxy lamination in production planning
• ✗Not specifying the tube material early in the design — it locks the available manufacturing process

05 — Possible solutions

• ✓Press-fit process: aluminium plate with CNC-machined grooves, copper tube inserted and mechanically deformed to fill the groove. No filler material — clean, no outgassing, ideal for contamination-sensitive applications (vacuum, optics, semiconductor, medical)
• ✓Press-fit constraint: applicable ONLY for aluminium plates with copper tubes. Stainless steel tubes cannot be press-fitted — their hardness prevents the plastic deformation required to fill the groove
• ✓Epoxy resin process: tube placed in the groove, thermally conductive epoxy fills the remaining gap. Compatible with any tube material (copper, stainless steel, brass) and any groove geometry
• ✓Thermal performance: both processes deliver equivalent thermal performance when correctly executed — choice should be driven by material and contamination constraints, not by heat transfer
• ✓Contamination control: prefer press-fit when the system must avoid any organic residue, outgassing, or long-term resin degradation
• ✓Use epoxy lamination when stainless steel tubes are required (corrosive fluids, high-pressure circuits, or specific chemical compatibility)

06 — Related topics