Designing for FDA/Caustic Washdown
E
quipment Applications.

More ways to win the battle against caustic washdown chemicals while maintaining FDA Compliance


Mike Quinn VP Sales & Marketing LM76


Caustic Foaming Agents are corrosive and can cause serious damage to balls, rollers, plastics, seals and lubricants.




Sanitation Standard Operating Procedures (SSOPs)

Consistently using correct cleaning and sanitizing procedures in dairy and food processing plants is the foundation to producing high quality, safe food. Sanitation Standard Operating Procedures (SSOPs) are detailed procedures specifying what to clean, how to clean, how often to clean and the records used for monitoring.

A food processing or beverage plants washdown areas are unique environments that undergo harsh abuse from pressure washer sprays and a multitude of chemicals used in the cleaning and sanitation of equipment.

In the baking industry, warm water and soap is a common washdown combination. However, meat, poultry and dairy products require more aggressive chemicals like sodas(sodium hydroxide) and self-foaming cleaners, foaming acids and self-foaming chlorinated caustic cleaners like chlorine to sanitize bearings, shafting and direct food contact areas.

At LM76, we understand the issues associated with FDA/Washdown compliant materials, as food contact and outside food contact applications and aggressive caustic foaming agents and sodas like sodium hydroxide.



Materials

These bearings and systems see some hostile treatment: high pressure washdown, caustic antibacterial foaming agents (some containing 10 -15% chlorine) and contact with fats, acids, oils and process chemicals.

For direct food contact 316L Stainless is preferred. It pays to use 316L on all food contact surfaces because regulators will accept it without question - 304 Stainless is also widley used. For additional corrosion resistance and hardness, our Marvalloy TDC has a terrific track record in many FDA compliant applications.  Link to Marvalloy PDF



1.5" and 2" NP-BB-ETX Pillow Block Assemblies Riding On 440c Stainless Shafts with Marvalloy TDC Coating


So you can build your machines in the conventional manner using 316L only where product contact is made. If you chose to use other than 316L material, then you must validate the long term effect of product contact with it. 316L is preferred for instance for its corrosion resistance, sanitation and sterilization capabilities. Materials should be not reactive, shed, or contaminate.

For our purposes at LM76, we use all the 300 Series Stainless grades: 316, 304 and 303. 316 is the hardest in this family and is less reactive. 304 is in the middle and 303 is the least in these qualities. 303 Stainless is easier to machine and this can make a difference in the final price of parts being manufactured. Our 300 Series Stainless, self lubricating (PTFE) FDA Compliant linear bearings are the typical choice of design engineers because they are readily accepted by inspectors and because our White PTFE is FDA Compliant and has no abrasive fillers, it can run on soft 300 series stainless linear shafting.



Ceramic Coated Linear Bearings are FDA Compliant

LM76 Ceramic Coated Linear Bearings consist of an aluminum substrate with a ceramic coating witch is file hard (Rc78) and will not chip, flake or generate debris. The ceramic coating is not just a surface treatment, it actually migrates into the aluminum substrate forming a truly tenacious wear surface. Ceramic Coated linear bearings offer low friction (.04-.08) coupled with smooth and quiet linear translation. Our Ceramic Coated linear bearings are unparalleled in high accelerations (over 150 G's) and system speeds - as a matter of fact, we have not found an acceleration or system speed where they have failed when properly employed in an application. Capable of blazing short stroke, rapid oscillations, Ceramic Coated bearings are used on the fastest gas compressor and mattress making machine manufactured today. They are also used on high production hamburger pattie press systems where they are in direct food contact (fat from the hamburger is the actual lubricant - less than comforting) with the hamburger. Ceramic Coated linear bearings were the first drop-in replacement for linear ball bearings (LM76 stands for Linear Motion and the company was founded in 1976) and they sparked a new interest in sleeve-style linear bearing material development. NOTE: Like Linear ball bearings, ceramic coated bearings are not self-lubricating, they must be lubricated.


Electroless Nickel Plated NP Pillow and Flange Blocks are an alternative
to 300 Series Stainless
We have been asked numerous times by customers to manufacture pillow blocks from 300 series stainless steel. But our experience is that no one wants to pay for them or wait 8 - 10 weeks for delivery. After searching for an answer, one all can live with, I decided to offer Electroless Nickel Plated - standard off-the-shelf pillow blocks. NP has been a huge success. Electorless Nickel is FDA and Caustic Washdown Compliant and offers a surface hardness of 72 Rc. NP pillow blocks will not flake, chip or generate debris. The additional cost is easily accepted by our customers and the knowledge they are in compliance, under budget and can receive product in a week is a win for them. NP pillow blocks and flange blocks can accept our Stainless PTFE/Self-Lubricating bearings, Fluidline (Closed Only), linear ball bearings and our ceramic coated (FDA compliant with FDA grease) linear bearings.

NP Plus Stainless FDA NP Plus Fluidline NP Plus All Stainless Linear Ball NP Plus Ceramic Coated

LM76 Stainless FDA/Self-Lubricating Linear Bearings

As a standard drop-in for industry linear ball bearings, LM76 standard off-the-shelf FDA bearings have snap ring grooves machined into the OD of the bearing. Although these are potential trap/inclusion areas, the optimum design is for a smooth OD - minus these grooves. We have supplied thousands of our standard FDA bearings and securing them in the housing with a stainless steel snap ring seems to have proven acceptable to inspectors.



ETX Snap-In Scraper Seals

LM76's ETX Scraper Seal is a game changer for companies in the cheese, dairy, and meat industries or any design that requires media or debris not get included between the bearing and the shaft. Designed by our company president John Tarbell, this innovation has found acclaim in our industry. The ETX-FDA Self-lubricating scraper seal has an interference fit with the shaft - scraping debris away from bearing/shaft interface. ETX Scraper Seals are designed to snap into the ends of our stainless FDA linear bearings. NOTE: Closed Bearings Only



Ceramic Coated FDA Bearings  1/3 the Weight of Stainless 30% Less Expensive

Ceramic Coated FDA Linear Bearings offer a FDA compliant ceramic coated aluminum shell that has FDA PTFE Self-Lubricating liner bonded to the bearing ID. Used mostly in applications where the weight of stainless is prohibitive. These bearings are approximately 30% less expensive than stainless linear FDA bearings and are only made to special order. Leads time approximately 3-4 weeks. These bearings can be modified to accept ETX-FDA scraper seals.


SPECIAL DESIGNS - "When Others Think Catalog...We Think SOLUTION"

At LM76, we think out-of-the box - a company core philosophy. What's possible? Just about anything. Here we have a unique example of this state of thinking. One of the largest brewers in the country approached us regarding an issue they were experiencing with standard, off-the-shelf PTFE bearings form another company. The liner of the bearing was wearing prematurely because fluids and debris were getting trapped between the bearing and the shaft. So much so, the bearings were sticking and causing servo motors to trip-out. We decided to design a one piece construction, self-lubricating bearing from our Fluidline, FDA material and machine ETX Scraper Seal into - integral in the bearing itself. We have since changed over 4 filling lines with this design. Our customer was so pleased, we were asked to meet corporate engineers at their plant and conduct a thorough linear audit which resulted in the special ETX block design seen below riding on a ceramic coated aluminum shaft extrusion.



Why you want to avoid linear ball bearing contact with product or position them over product.

Linear ball bearings are mechanical systems: races/retainers, balls, lubricants and seals to retain the lubricants.

1. The FDA does not want linear ball bearings above product because of potential catastrophic failure - balls
    and metal debris falling into product.
2. Linear Ball Bearings can include - debris can get under the seal - product which can produce bacteria and lead to bearings failure.
3. Seals and Lubricants may not survive the chemicals and foaming agents.



NP-BB-ETX  
LM76 has designed a FDA/Self-Lubricating/Washdown Complaint Scraper/Seal Cartridge which we have successfully used with both fixed, all stainless and self-aligning linear ball bearings where low friction and FDA/Caustic Washdown compliance is required. The ETX Scraper Seal has an interference fit over the shaft so it successfully snowplows debris aside - will not allow debris to include in the ball circuits. Additionally, ETX seals help maintain grease volume within the bearing assembly during high pressure washing.

NP-440C-OH (ETX Optional)
The next time you look at a steel jacketed linear ball bearing, take note that there is no oil hole through the bearing shell - you can't re-lubricate.
How strange...since a linear ball bearing requires lubrication. I think LM76 is one of the few who noticed this odd fact and said, "That's not right." So we decided to supply our stainless linear ball bearings with an oil hole. Our NP-440C-OH pillow block has a zerk fitting which lines-up with the bearing oil hole so you can re-lubricate externally. To maintain anti rotation and oil hole/zerk fitting registration, we create a flat on the opposing side of the bearing shell - retaining position with a stainless set screw.

1. Flat  2. Set Screw  3. Zerk Fitting  4. Oil Hole

WD2 Water Dog Channel Sliders

Water Dog Sliders represent a fundamental design idea, are easy to use & install and are the only product of their kind that runs in an all 300 series stainless channel. Water Dog Sliders love water, have 3 times the abrasion resistance than steel, offer low running friction, quiet and smooth operation and resist - unlike traditional sleeve bearings - edge loading. A very inert system that can see almost any chemical or contaminant. FDA Compliant and Caustic Washdown Compliant. The WD Slider Block will not allow - cheese for instance - to stick or adhere to it. Water Dogs provide a flush channel running along their bottom for fluid/debris evacuation and have an extremely positive fastening system: 4) 1/4-20 Stainless Nuts which come with the block. One of our customer's Sargento Cheese has used them successfully on their process lines.


FDA/Washdown Compliant Linear Shafting

Choosing Linear Shafting for FDA/Caustic Washdown applications is critical to the success of your design. LM76 offers Case Hardened 440C Stainless Steel, 316, 304 and 303 stainless. We offer our Marvalloy TDC coating which enhances corrosion resistance while increasing shaft hardness to Rc78.

        Round Stainless Shafting Class L Fully Supported Stainless Shaft Assemblies Machined-to-Print Specials

FDA Compliant Special Coatings for Linear Shafting

LM76 has many options when special FDA compliant coatings are required. We can coat shafts with our Marvalloy TDC coating and we can ceramic coat aluminum supports and end support blocks or electroless nickel plate them. Additional corrosion resistance and compliance is relatively inexpensive and lead times are short.  Link to Marvalloy PDF


For more information or application review, please call Mike Quinn @ 1-800-513-3163
or email:
mquinn@LM76.com   


www.LM76.com                           www.LM76LinearBearingSolutions.com