What are the different types of welding and polishing specifications?

Every MPI magnetic separation product proposal or order will include finish specifications. These specifications detail the welding and polish specifications of how MPI will fabricate the equipment.

MPI Finish Specifications Selection Guide

	WELD	CODE	QUALITY	COST	DESCRIPTION
	Industrial Stitch Weld	1Z	•	•	[1] = Product contact areas are stitch welded. [Z] = Product contact areas are ceramic bead blasted or polished to “reduce” scratches and burns. Scratches and burns may still be present.
	Industrial Seam Weld	2Z	• •	• •	[2] = Product contact areas are continuously welded. Some welds may or may not be ground. [Z] = Product contact areas are ceramic bead blasted or polished to “reduce” scratches and burns. Scratches and burns may still be present.
	Food Grade	2X	• • •	• • •	[2] = Product contact areas are continuously welded. Some welds may or may not be ground. [X] = Product contact areas are polished to remove scratches/burns (80 grit minimum). Hard-to-reach areas may be ceramic bead blasted for a uniform finish.
	Food Grade Sanitary	3X	• • • •	• • • •	[3] = Product contact areas are continuously welded “sanitary” with no pits, cracks, or crevices. Some welds may or may not be ground. [X] = Product contact areas are polished to remove scratches/burns (80 grit minimum). Hard-to-reach areas may be ceramic bead blasted for a uniform finish.
	Dairy/Meat/Pharmaceutical	4W	• • • • •	• • • • •	[4] = Product contact areas are continuously welded “sanitary” with no pits, cracks, or crevices. All welds are ground. [W] = Product contact areas are polished to remove scratches/burns (180 grit minimum).
	USDA AMS Dairy, Meat and Poultry Certification	USDA	• • • • • •	• • • • • •	[USDA] = USDA Approved Certified Sanitary (USDA AMS NSF / ANSI / 3-A SSI-14159-1) Product contact areas are continuously welded “sanitary” with no pits, cracks or crevices. All welds are ground. All surfaces are polished to a 32 Ra µm. All fillet welds ground to a (.125”) radius on materials less than (.187”) thick; (.250”) radius on materials (.187”) thick or greater.

MPI Manufacturers to the Highest Standards

To comply with various industry standards across a wide range of industries that MPI serves, MPI has developed its own internal standards to meet industrial, food, dairy, and pharmaceutical requirements of customers, industry associations, or governmental agencies. Where possible, MPI has used industry terms to align our internal standards and has earned rigorous certification and testing to offer 3rd party certified sanitary standards. MPI can fabricate the equipment to customer-specified standards when requested. If you have questions or requested modifications to the standards proposed with your product, you can work with our team to ensure you get the right final product finish for your application.

MPI breaks down finish specifications into two categories, product contact, and non-product contact areas.

Product Contact Area

The product contact area is anywhere where the product can come into contact with the surface of the equipment during regular operation. This is generally inside the equipment and can include the magnet tubes, steps, diverters, and internal housing seams.

Non-Product Contact Area

The non-product contact area is anywhere on the device that the product does not come into contact with the equipment during regular operation. This is generally outside the equipment and can include the external housing seams, hinges, latches, and flanges. In many cases, the product contact areas may have a different finish than non-product contact areas.

Magnets magnetically capture and control ferrous contaminants in material process systems. The proper magnetic applications and magnet placements will help you achieve success for removing tramp metal from your product flow.

What is a USDA Certification?

Information about MPI’s USDA Certification:

MPI has worked with the United States Department of Agriculture (USDA) Marketing and Regulatory Programs Agricultural Marketing Service (AMS) to certify specified MPI magnetic separators to meet the following standards:

• USDA Guidelines of the Sanitary Design and Fabrication of Dairy Processing Equipment
• NSF/ANSI/3-A SSI-14159-1 (Hygiene Requirements for the Design of Meat and Poultry Processing Equipment)

These standards require the equipment to meet the following:

• Durable, corrosion-resistant and non-absorbent
• Sufficient in weight and thickness to withstand repeated washing
• Smooth finishing, and easily cleanable surface
• Resistant to pitting, chipping, crazing, scratching, scoring, distortion and decomposition

MPI Magnet Experts Offer Recommendations

MPI offers six types of weld and polish finish specifications including a USDA certification to meet the stringent food safety guidelines. Our magnet experts will assist you with determining the best weld and finish specifications for your bulk gravity, pneumatic, liquid, and metal sorting applications.