In many different industries it's a requirement that parts, products, and/or handling equipment undergo frequent cleaning and sterilization to prevent contamination. Many medical/pharmaceutical, food, and precision engineering applications require incredible sterility and cleanliness to maintain safety and quality standards.
Recently, an overseas manufacturer contacted Marlin Steel to create a custom stainless steel cart to hold multiple baskets and contents through a sterilization process.
Meeting the Needs of Many Parts
The customer had a large-capacity sterilization system that used a massive chamber to sterilize parts on a large scale. However, they also needed a way to quickly move parts in and out of the sterilization chamber to optimize production speeds.
So, the client contacted Marlin Steel to create a specialized sterilization basket cart. The clients would take baskets directly from the previous manufacturing step and load them onto the cart, and then push the whole cartload of baskets into the sterilization chamber. Once the process was finished, the baskets would be removed and taken to the next step of the process. Then, the cart would be reloaded for another sterilization cycle.
The primary challenges for this design were to:
- Ensure the cart could withstand the sterilization process (temperature, chemical, and other stress factors);
- Make sure the sterilization cart was easy to load and unload;
- Reinforce the cart’s frame to withstand heavy parts loads and carry several different basket types; and
- Keep plenty of open space between baskets so the sterilization process could work at peak efficiency.
Making the Sterilization Cart
Given the large size of the sterilization chamber, this custom cart could be a bit different in size and shape from the stock cart designs Marlin has. Instead of a square base, this cart would use a long, rectangular one. The longer shape of this cart would allow the client to mount more baskets at once, helping optimize processing time by sterilizing more parts at once.
Instead of freely rotating caster wheels, this cart instead used fixed wheels on linear mounts that were mounted parallel to the length of the frame. This would help make it easy to push and pull the cart straight into and out of the sterilization chamber without it shifting side to side—saving time on mishandling.
To maximize the cart’s structural integrity, a series of large crossbars were added to the frame across the top and bottom, with four more reinforcing bars connecting the top and bottom portions of the frame. Other, smaller crossbars were added to each level of the cart to further reinforce individual rows to hold heavy loads—several of these smaller crossbars were welded directly to either the frame or to one of the larger reinforcing crossbars to improve structural integrity.
Finally, to ensure the cart could withstand repeated exposure to a sterilization process that would use high temperatures and mild surfactants, the cart would use a stainless steel alloy rather than plain steel. Grade 304 stainless steel has a better overall resistance to different chemicals than plain steel because of its protective oxide layer that acts as a barrier against contamination.
To ensure this design concept would actually hold up under the client’s sterilization process for numerous uses, Marlin’s engineers then tested the design using Finite Element Analysis (FEA) software. This software enabled the Marlin team to virtually test the cart design against the use conditions specified by the client and identify any major flaws that would lead to premature failure.
The benefit of this FEA analysis was that it allowed the engineers to test the cart for thousands of uses in mere minutes rather than months, speeding up the quality control process significantly, while also spotting issues that would only become apparent after prolonged use. This helped Marlin Steel save the client time and money on testing prototype baskets—especially considering the delay that international shipping imposed on delivering a physical prototype.
In the end, the client was able to take the carts Marlin made and put them to use right away to streamline their sterilization process. Learn more about Marlin’s custom stainless steel carts by contacting us today!