OLA

Case Study: Ball-Stack Lattice Heat Exchanger Core

316L Stainless Steel | Selective Laser Melting (SLM) | Compact Thermal Management

Metal 3D Printing Application

1. Background

An industrial thermal-systems OEM was developing a next-generation compact heat exchanger for a high-temperature process gas stream. The legacy finned-tube design had reached its surface area limit: it was too large for the available installation envelope, and brazed joint failures were causing costly downtime. The engineering team needed a breakthrough in volumetric heat transfer density that conventional manufacturing could not deliver.

2. The Challenge

Design requirements included:

· Triple the heat transfer surface area within the same installation envelope

· Operate continuously at 600 °C in a corrosive process gas environment

· Eliminate all brazed joints — fully monolithic construction for leak-free service

· Withstand thermal cycling between 25 °C and 600 °C without fatigue failure

· 50% weight reduction compared to the legacy finned-tube design

· Deliverable in under 4 weeks for prototype validation

3. The Solution

The heat exchanger core was redesigned as a monolithic ball-stack lattice structure, manufactured by Selective Laser Melting (SLM) in 316L stainless steel. The geometry consists of thousands of identical micro-spheres (~3 mm) arranged in a regular orthogonal array, each sphere fused to its neighbors at the contact points to form a continuous, leak-tight porous matrix. This topology delivers an unprecedented surface-area-to-volume ratio — impossible to produce by conventional machining, casting, or brazing — while preserving the open flow paths needed for both hot and cold fluid streams.

 

Figure 1: SLM-printed 316L ball-stack lattice core — vertical orientation, integrated base plate for direct mounting

4. The Result

· 3× heat transfer — surface area vs. legacy finned-tube design in the same envelope

· Zero leak paths — fully monolithic, no brazed joints or weld seams

· 50% weight reduction — vs. conventional stainless finned core

· Lead time: 3 weeks — from CAD to finished printed core

· Continuous service — verified at 600 °C in corrosive process gas

· Full certification — 316L / ASTM A276, RoHS & REACH compliant

“The ball-stack lattice delivered heat transfer density we did not believe was possible in a stainless part. It has been in continuous high-temperature service for over six months with zero maintenance events.”

 

Figure 2: Horizontal mounting orientation — demonstrates geometry flexibility for different flow configurations

 

Figure 3: Close-up view of the ball-stack array — uniform 3 mm spheres fused at contact points, 316L

 

Material: 316L Stainless Steel  |  Process: SLM / Metal 3D Printing  |  Application: Compact Heat Exchanger Core