You buy a robot rated IP65 for a food plant, hose it down once a shift, and six months later the gearbox is full of water. The datasheet said washdown. The datasheet didn’t say which direction the water comes from.
What the first digit means
The IP code has two digits. The first is solid particle protection: 5 means dust-protected, 6 means dust-tight. For a food or pharma plant, you need 6. IP54 will let dust in over time, and dust plus water makes a sludge inside the wrist.
The second digit is water protection. IPX1 is dripping water. IPX3 is spraying water up to 60 degrees. IPX5 is low-pressure jets from any direction. IPX6 is high-pressure jets. IPX9K is high-temperature, high-pressure close-range cleaning, the kind a washdown crew uses with a steam lance.
The mistake is reading “IP65” as “you can hose it down.” IP65 survives low-pressure spray. It does not survive a 100 bar steam lance held six inches from the joint. That’s IP69K territory.
What the datasheet doesn’t tell you
Ratings are tested at the factory on a new robot, with all cable connectors seated and the wrist in a specific position. Once you mount a gripper, run cables through the dress pack, and drill a valve block onto the forearm, you’ve created new entry points. The robot’s rating doesn’t cover your end-of-arm tooling. The gripper, the valves, and the sensors on it need their own ratings.
This is where washdown cells fail. The robot is stainless and sealed. The gripper is aluminum with a bare bearing. The valve has a vent hole. The maintenance team hoses everything down because the robot is rated for it, and the cheap components inside the gripper corrode in three months.
Stainless vs painted
A painted steel robot in a washdown environment looks fine until the paint chips. Once the chip reaches base metal, rust spreads under the paint and you can’t see it. Stainless steel bodies cost more upfront but survive repeated cleaning without a paint system to maintain.
For dry machining or assembly, a standard painted robot is fine. For food, pharma, or anywhere you hose the equipment, spend the money on stainless. The difference in cleaning time alone pays for it.
Cable management under pressure
The dress pack is the weak point. Cables flex, the cable glands loosen, and water finds the spiral wrap. Use food-grade cable with sealed connectors rated for washdown. Don’t rely on conduit that splits along the seam after a few months of heat and water.
Route cables away from the spray direction where possible. If a cable has to cross a washdown zone, give it a drip loop so water doesn’t run along the jacket into the connector.
Bottom line
Match the IP rating to the actual cleaning method, not to the word “washdown” in the catalog. If the crew uses a high-pressure hot lance, specify IP69K on the robot, the gripper, and every component in the cell. If they wipe surfaces, IP65 is overkill. Ask the cleaning crew what they actually do before you buy.
