Choosing the Right Mechanical Separator for Your Process
By: Nathan Kodesh, Thomas Precision LLC, June 2026
Belt, slow speed, and high speed separators each recover usable product in a different way. Understanding how they differ is the key to protecting yield, texture, and product quality — and to matching the right machine to the right job.
Which Separation Method Is Right for Which Product or Process?
Mechanical separation increases profitability by recovering usable product that would otherwise be lost to the waste stream — meat left on bones after deboning, fish pinbone strips and trim, sinew-laden meat, or even product trapped inside its own packaging. The challenge is that no single machine is ideal for every application. A line producing a premium, low-bone, product has very different needs than one reclaiming the last usable protein from frames and trim, or one pushing high tonnage of mechanically deboned meat (MDM/MSM) for further processing.
The decision usually comes down to a handful of factors: the raw material you are feeding (soft trim vs. bone-in frames, wet vs. dry, large vs. small pieces), the end product you need (a textured or ground product vs. a fine paste), your target yield and bone/calcium content, your required throughput, and practical realities like temperature rise, footprint, and maintenance. Broadly, the industry sorts mechanical separators into three families based on how gently and how fast they work the product. The sections below explain each family, what they typically run, and their respective advantages and trade-offs.
Belt Separators (Soft Separators)
How they work. A belt separator — often called a soft separator — uses a perforated, rotating drum paired with a moving separation belt. Product is drawn in where the belt and rotating drum meet, pre-squeezed by a carriage that maintains a controlled belt-to-drum gap, then given a final high-pressure squeeze by a pressure roller that firmly sandwiches the product between the belt and drum. Soft product is pushed through the holes in the drum and discharged out the center; harder material rides the belt out the side to a discharge chute. Because the product is briefly squeezed rather than ground, its natural texture is largely retained.
The belt material can be specified from soft to hard depending on the input product, and both the drum hole size and the pressure roller setting are variable to dial in yield or throughput.
COMMONLY PROCESSED PRODUCTS
- Premium, low-bone meat for human consumption, trim and frames including poultry, pork, and beef.
- Boneless fish meat from pinbone strips, collar bones, fillets, and trim
- Desinewing — separating connective tissue from meat to create uniform textured or sausage raw material
- Fruit and vegetable purees, juices, and dewatering applications
- Depackaging and reclaim — recovering cheese, butter, packaged hot dogs and sausages for rework
- Reworking product compromised with foreign material by running it through a very-small-hole-size drum
- Reclaiming additional protein from bone-collect waste pulled off a grinder, or from the refuse of another separator. Sometimes referred to as a “second pass” machine.
ADVANTAGES
- Gentlest separation; produces high-quality, low-bone product
- The lowest temperature rise of the three families — valuable for delicate or temperature-sensitive product
- Highly adjustable yield and texture via belt material selection, drum hole size, and pressure settings
- Lowest horsepower requirement
- Exceptionally versatile, including non-meat and depackaging tasks
TRADE-OFFS
- More mechanical and electrical components and wear parts, which can make maintenance and troubleshooting more complicated
- Large or hard pieces can be difficult to draw in at the belt/drum contact point; an additional pre-crusher or pre-cutter may help
- More parts to clean
- Belt life varies with product and pressure and must be monitored for wear or failure
- Drums and drum scrapers require periodic sharpening or replacement as they wear. A coated drum can extend the life of the drum and scraper blade.
Slow Speed Separators (Deboners)
How they work. A slow speed separator uses an auger (screw) turning at a low RPM to squeeze product through a perforated screen. Soft product is forced through the holes while harder material is carried to the end of the screw, where a ring valve or restrictor acts as an adjustable choke point to control yield and calcium/bone content. The screw’s variable flight pitch and body diameter, along with the choke point, build the pressure that drives separation. Turning the auger slowly gives a slower, gentler separating action than a high speed machine, which helps protect product texture and limit temperature rise.
These machines are typically built as an “all-in-one” unit: their own hopper, a feed screw, and an in-line pump (or a dual-screw pump infeed) that provides positive product flow into the separation screw. That built-in feed system is especially useful with wet or low-bone product and eliminates the need for a separate pump or grinder to feed the machine. A discharge pipe can often be fitted on the good-product discharge to move recovered product several feet toward the next step in the process. The term “slow speed separator” is a descriptive one; these machines are also widely referred to simply as deboners.
COMMONLY PROCESSED PRODUCTS
- Mechanical deboning of chicken, turkey, pork, and beef
- Bony trim reclaim
- Desinewing of beef shank, cartilage, and similar cuts of meat
- Pork de-fatting and gelatin applications
- Vegetable peel dewatering to cut transport costs
- Reclaiming additional protein from bone-collect waste pulled off a grinder, or from the refuse of another separator. Sometimes referred to as a “second pass” machine.
ADVANTAGES
- Gentle, low-RPM action yields consistently textured product with low temperature rise
- All-in-one design needs no separate feed pump or grinder
- More compact footprint than a comparable high speed setup
- Interchangeable screen hole sizes and patterns to balance yield and calcium
TRADE-OFFS
- Lower throughput than high speed separators
- More parts than a single high speed separation head (though roughly comparable once a high speed machine’s feed pump or grinder is included)
- Although compact, these machines can still get quite long
High Speed Separators
How they work. A high speed separator uses the same fundamental screw-and-screen principle as a slow speed machine — soft product is pressed through a perforated screen while hard material moves to a ring valve or restrictor that controls yield and calcium — but the auger turns much faster. That higher speed drives the highest throughput of the three families and is the workhorse of high-capacity MDM operations (also referred to as MSC, MST, or MSB depending on the product). Machines can be belt-driven, or, in top-of-the-line configurations, directly driven for efficiency and durability.
Unlike the all-in-one slow speed design, a high speed separator is fed by a separate pump or grinder. That adds some cost and footprint, but it also is the key to achieving the higher throughput rates. It also enables the operator to balance the product flow into the separator to optimize yield and separation consistency. The faster, more aggressive separation tends to raise product temperature more than the other two methods, though it can also deliver higher yields. High speed separators are also widely used in the pet food industry, where looser bone and calcium requirements and larger screen hole sizes allow them to produce quality product at even higher yields and throughput rates. Like slow speed machines, high speed separators offer a range of screen hole sizes and patterns to balance yield and calcium.
COMMONLY PROCESSED PRODUCTS
- High-capacity mechanically deboned/separated meat (MDM/MSM) from poultry frames and parts (MSC, MST), and beef (MSB)
- Pork, lamb, and other red-meat applications
- Both human-food and pet-food end products, depending on configuration and pressure
- Note: Fish is not commonly run on high speed separators. Belt or low speed separators are typically used
ADVANTAGES
- Highest throughput and capacity of the three families
- Potential for higher yields
- Fewer parts on the separator itself and easier to assemble with lighter weight parts/tooling
- A separate feed pump or grinder allows precise control of product flow into the machine
- Available in belt-driven or premium direct-drive configurations
- Some manufacturers now offer “on-the-fly” yield adjustments to reduce downtime
TRADE-OFFS
- Highest horsepower requirement
- Higher temperature rise due to the speed and rate of separation
- Requires a separate pump or grinder, adding cost and footprint
- Generally not recommended for fish
Quick Reference Guide to Separator Families
General guidance. Optimal selection depends on raw material, target yield, end product, and line capacity.
Across all three families, hole size and pattern, separation pressure, and feed rate are the primary levers for balancing yield against bone/calcium content and finished-product texture. The right starting point is defined by your raw material and the product you need to make.
A Full Line of Separation Options from Thomas Precision
Thomas Precision offers a complete range of mechanical separation equipment spanning all three families — from compact belt separators handling as little as 50 lbs/hour to high speed machines reaching 42,000 lbs/hour. Whether your priority is the gentlest possible handling of a premium product, a versatile all-in-one deboner, or maximum capacity from a high-volume MDM operation, there is a Thomas Precision solution sized and configured for the job.
About the Author:
Nathan Kodesh is the Director of Engineering and Service, Thomas Precision LLC. Nathan has spent the past 14 years at Thomas Precision, where he leads the engineering and service departments. The role has given him deep knowledge of the manufacturing processes, equipment, and parts used by food processing OEMs and related industries. Before joining Thomas Precision, he spent 9 years with Hormel Foods in various engineering and supervisory roles across multiple locations. He holds a degree in Manufacturing Engineering from the University of Wisconsin–Stout.