Gantry CNC Milling an SS400 Chrome-Plated Bracket with 0.05 mm Flatness Control
Richconn produced a thin SS400 bracket for automation equipment. The part was only 5 mm thick and required deformation control, smooth machined textures on the outer profile and inner cavities, flatness within 0.05 mm, and final chrome plating.
Thin SS400 Bracket with Deformation Risk and Chrome Plating Requirement
This project involved gantry CNC milling of a custom SS400 bracket used in automation equipment. The part thickness was only 5 mm, making it sensitive to deformation during machining.
The customer required the outer profile and inner cavities to be machined smoothly, with the final flatness controlled within 0.05 mm. The part also required chrome plating, so deformation control had to be considered both before and after surface treatment.
Technical drawing reference for the SS400 bracket, showing the complex profile and internal cavity structure that required controlled machining allowance and flatness correction.
Why This Thin Bracket Was Difficult to Machine
The customer’s main concern was machining deformation. Because the bracket was only 5 mm thick, the material could easily deform under tool force during machining.
For a thin custom bracket with an irregular outer profile and inner cavities, both the cutting strategy and post-machining correction were important to ensure assembly accuracy.
Main Manufacturing Risks
- The 5 mm thickness made the bracket sensitive to cutting force and deformation.
- Inner cavities required controlled allowance and stable final milling.
- Laser cutting could leave burrs or heat-affected distortion if not managed properly.
- Flatness needed to be corrected and controlled within 0.05 mm.
- Chrome plating could introduce additional deformation or surface variation.
- Final dimensional and appearance inspection was required to support reliable assembly.
The Core Difficulty Was Deformation Control on a Thin 5 mm Steel Bracket
The main issue was the relationship between part thickness, cutting force, and flatness stability. Because the SS400 bracket was thin, tool pressure during machining could cause the material to deform. If the outer profile, inner cavities, and post-plating correction were not controlled together, the final flatness could exceed the customer’s requirement.
| Thickness Risk | The bracket thickness was only 5 mm, making the part more likely to deform under cutting force. |
|---|---|
| Inner Cavity Risk | The internal cavity structure required controlled allowance and precise milling to avoid deformation and burr-related problems. |
| Flatness Requirement | The final flatness needed to be controlled within 0.05 mm to meet the customer’s assembly requirement. |
| Surface Treatment Risk | After chrome plating, the part required another correction step to maintain the required flatness and appearance quality. |
How We Controlled Deformation, Burr Risk, and Final Flatness
Richconn used a process route that combined laser cutting, controlled machining allowance, gantry CNC milling, manual flatness correction, chrome plating, and post-plating correction. The goal was to reduce deformation risk while keeping the outer profile and inner cavities smooth.
Laser Cutting Outer Profile
The outer profile was cut by laser first, preparing the rough shape while keeping the internal cavity allowance for later machining.
0.5 mm Allowance for Inner Cavities
The inner cavities were left with a 0.5 mm allowance, reducing risk before final CNC milling to size.
Gantry CNC Milling to Final Size
A CNC gantry milling process was used to machine both the outer profile and inner cavities to the final required dimensions.
Manual Flatness Correction
The product was manually corrected after machining to bring the flatness within 0.05 mm.
Chrome Plating
After machining and correction, the SS400 bracket received chrome plating according to the customer’s surface requirement.
Post-Plating Correction
After chrome plating, the part was corrected again to maintain flatness and meet the final assembly requirement.
Dimensional Inspection
Each part was checked for key dimensions to verify stable delivery quality and reliable assembly fit.
Appearance Inspection
Appearance inspection was performed to confirm smooth tool marks, no obvious burr residue, and acceptable surface quality.
mm flatness achieved after machining, correction, chrome plating, and post-plating correction
thin SS400 bracket thickness successfully controlled for automation equipment assembly
Smooth Outer Profile, Smooth Inner Cavities, and Flatness Within 0.05 mm
After process control, the bracket’s outer profile and inner cavities had smooth machined textures, and the flatness was controlled within 0.05 mm. The finished chrome-plated parts met the customer’s requirements for assembly and use.
- Material: SS400 steel
- Surface treatment: chrome plating
- Process: laser cutting + CNC gantry milling
- Quantity: 3 pieces
- Part thickness: 5 mm
- Inner cavity allowance before milling: 0.5 mm
- Flatness after correction: within 0.05 mm
- Final control: correction again after chrome plating
What Buyers Should Know About Thin Steel Bracket Machining
Thin steel brackets are easy to underestimate. Even when the geometry looks simple, cutting force, laser cutting effects, internal cavities, and surface treatment can all influence final flatness and assembly fit.
For complex irregular brackets, the process should be planned around deformation prevention, controlled allowance, burr control, correction strategy, and final dimensional and appearance inspection.
Richconn’s Practical Experience
- Use laser cutting to prepare complex outer shapes efficiently.
- Leave controlled allowance for internal cavities before final milling.
- Use gantry CNC milling for large or irregular bracket structures.
- Correct flatness before and after chrome plating when deformation risk remains.
- Inspect both dimensions and appearance before delivery.
- Optimize cutting strategy to reduce deformation and burr residue.
Related CNC Machining Services
Richconn supports custom CNC machining of SS400 steel brackets, automation equipment parts, chrome-plated components, thin plates, fixtures, mounting brackets, and complex custom metal parts based on customer drawings.
FAQ About Thin SS400 Bracket CNC Machining
Why do thin steel brackets deform during CNC machining?
Thin steel brackets can deform because the part has limited rigidity. Cutting force, clamping pressure, material removal, and surface treatment can all affect final flatness.
Why was 0.5 mm allowance left in the inner cavities?
Leaving allowance before final CNC milling helps reduce processing risk and allows the internal cavities to be finished accurately after rough shaping.
Why was correction needed again after chrome plating?
Surface treatment can introduce additional stress or slight shape changes. Post-plating correction helps keep the final flatness within the required range.
Can Richconn machine similar thin chrome-plated brackets?
Yes. Richconn can support custom CNC machining of SS400 steel brackets, thin plates, chrome-plated components, automation equipment parts, and complex irregular parts based on drawings, materials, tolerances, and surface treatment requirements.
Need a Thin Steel Bracket Machined with Flatness Control?
Send us your 2D drawings, 3D files, material requirements, thickness, internal cavity details, flatness requirements, surface treatment notes, and quantity. Richconn’s engineering team will review manufacturability and provide a practical CNC machining solution.