How to Properly Grind Raw Materials Before Entering a Dry Type Dog Food Processing Machine？

What is the Ideal Grinding Size?

For stable production in a Dry Type dog food pellet maker machine, 100% of raw materials should be ground into a fine powder with a particle size of 0.5mm to 1.0mm (approximately 60–80 mesh).

The Rule: The particle size should never exceed 1/3 of the die hole diameter. (e.g., for a 3mm pellet, the maximum particle size is 1mm).

The Reason: Dry Type dog food manufacturing machines rely on mechanical friction to generate heat. Coarse particles prevent even heat distribution, leading to "raw" centers and fragile pellets.

1. Grinding Benchmarks: Ingredient Specifics

Hammer Mill Grain Grinder - Operation Video

I'm interested in this model

2. Why "Precision Grinding" is Non-Negotiable for Dry Type dog food pellet mills

Dry type machines do not have the luxury of steam pre-conditioning. Therefore, the physical state of the powder determines the success of the "cooking" process.

I. Surface Area & Heat Transfer

Smaller particles have a larger surface-area-to-volume ratio. This allows the friction heat generated by the screw to penetrate the center of the particle instantly.

Result: 90%+ starch gelatinization, making the food highly digestible for dogs.

II. Expansion & "The Crunch"

Dog food needs a specific "crunch" or texture.

• If too coarse: The air pockets formed during expansion will be uneven, causing the kibble to be too hard or too brittle.
• If optimal: You get a uniform, porous structure that dogs enjoy and that holds its shape.

III. Die and Screw Protection

Large, unground fragments (like corn husks or bone bits) act as abrasives. They cause "micro-pitting" on the screw surface and can quickly clog the small holes of the die plate, leading to dangerous pressure spikes.

3. Step-by-Step: The Professional Grinding Workflow

• Magnetic Separation: Pass all raw grains through a permanent magnet to remove metal scraps. A single piece of wire can ruin a hammer mill screen or an extruder screw.
• Primary Hammer Milling: Use a high-speed hammer mill (2800-3600 RPM) to pulverize the mix.
• Sifting (The Quality Gate): Use a vibrating screen after grinding. Any material that doesn't pass the 1.0mm mark should be sent back for re-grinding.
• Homogeneous Mixing: Add micro-ingredients (vitamins/minerals) after grinding to ensure they aren't lost in the dust collection system of the hammer mill.

★Click to view more information about hammer crushers.

4. FAQ: 

Q1: Why is my dog food surface rough and "hairy"?

Answer: This is almost always due to insufficient grinding of fibrous materials. Long fibers don't melt or expand; they stick out of the pellet surface. Use a finer screen (0.8mm) for your fiber sources.

Q2: Can I grind ingredients together, or should I do them separately?

Answer: For dry extruders, joint grinding (grinding the whole mix) is often better. The harder grains help "push" oily or soft meat meals through the hammer mill screen, preventing clogging.

Q3: How does moisture affect grinding efficiency?

Answer: Raw materials should have a moisture content of less than 14% for grinding. If the grain is too damp, it will "paste" onto the hammer mill screen, reducing output and causing the motor to overheat.

Q4: Will fine grinding make the dog food too dusty?

Answer: No. Once the fine powder enters the extruder and is mixed with water/oil and heat, it turns into a cohesive dough. The finer the powder, the less dust the final dried kibble will produce because the "binding" is stronger.

Final Verdict: The 1% Rule

In the pet food industry, 1% of the investment in a good hammer mill and screen can save 20% of the cost in wasted energy and rejected product at the extruder.

For Startups: Don't skip the sifter.

For Quality Control: Check your screen for holes daily.

👉Get the latest quote