Designing for FDA/Caustic Washdown
Equipment
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
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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.
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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
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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. |
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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.
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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. |
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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. |
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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. |
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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 |
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