Premature corrosion and pitting on NXB-GEN-833-002 Washer and Spacer Set

Description

We are experiencing an issue with the NXB-GEN-833-002 Washer And Spacer Set installed on our R-20 robot, specifically on the J4 and J5 axes. The robot operates in our food packaging facility, which undergoes a daily caustic washdown procedure. We purchased these sets approximately three months ago during a scheduled preventative maintenance cycle. Over the last two weeks, our technicians have noticed visible rust and pitting on the surface of the washers. The product description specifies 304 stainless steel, which we expected to hold up in our environment. This premature degradation is concerning, as it could lead to joint contamination or failure. We have used other 304 SS components in this area without such rapid corrosion. We need to understand why this is happening and what the recommended course of action is, as we cannot risk particulate contamination in our product line.

Symptoms

• Visible rust spots and pitting on washer surfaces
• Brown discoloration in the joint's lubricating grease
• Increased friction noted during manual axis movement checks
• Component degradation in less than 90 days of service

Resolution

After receiving the customer's failed parts via RMA, our materials lab performed an analysis. The investigation confirmed the components were indeed 304 stainless steel. However, analysis of the surface residue and pitting pattern was consistent with corrosion caused by exposure to high-concentration chloride-based cleaning agents. Standard 304 stainless steel can be susceptible to this type of corrosion. As a goodwill gesture under warranty, we provided the customer with a replacement set manufactured from 316L stainless steel, which offers superior resistance to chlorides. We also advised the customer to review their cleaning agent's material safety data sheet (MSDS) and cross-reference it with material compatibility charts for future maintenance planning.

Resolution Steps

1. Issued RMA #77419 to the customer to return the corroded washer and spacer set for analysis.
2. Shipped a standard replacement NXB-GEN-833-002 set to the customer to prevent extended downtime.
3. Received and forwarded the customer's parts to the NexBot materials engineering lab.
4. Lab analysis confirmed the material as 304 SS and identified chloride-induced stress corrosion as the root cause.
5. Communicated findings to the customer and explained the material limitations of 304 SS in their specific chemical environment.
6. Authorized a one-time, no-cost upgrade to a custom-machined 316L stainless steel version of the washer and spacer set.
7. Confirmed with the customer that the new 316L set was received and installed without issue.
8. Updated the customer's site profile to note the requirement for 316L grade steel in their washdown environment.