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Granulator Knowledge Base
Practical guides on industrial granulators, granulator knives, equipment selection, and ZERMA America and Virtus Equipment machine applications — written by our parts specialists in Fort Myers, FL.
Equipment Selection
When Your Plastic Scrap Needs a Granulator, Not a Shredder
Not every piece of plastic scrap belongs in a granulator. A granulator produces a uniform, controlled regrind particle — ideal for direct reuse in injection molding, extrusion, or blow molding. A shredder reduces bulk volume but does not control particle size. Understanding the difference helps you choose the right machine for your material, your throughput, and your downstream process. This article covers the key decision points: material type, desired output size, feed form, and whether a combination shredder-granulator makes sense for your application.
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Industrial Plastic Granulator: Not the Office Kind
Industrial plastic granulators are a different category entirely from the document shredder under your desk. A central granulator, beside-the-press granulator, or heavy duty granulator uses a high-speed rotor fitted with precision-ground rotor knives and stator bed knives to reduce plastic parts, runners, sprues, and scrap into consistent regrind. This article breaks down how granulators work, the main machine types — low speed granulators, central granulators, heavy duty granulators, pipe and profile granulators, and beside-the-press models — and what each is built for.
Read Full ArticleMaintenance
Signs Your Granulator Knives Need Replacement
Worn granulator knives cost you more than a new set — in downtime, energy, and off-spec regrind. Increased particle size, rising motor amperage, unusual noise or vibration, and visible chipping or rounding of the cutting edge are all early indicators that your rotor knives or stator bed knives are approaching end of service life. This guide walks through each warning sign, explains what causes it, and covers how to inspect knife clearance and edge condition on Virtus Equipment and ZERMA America granulators.
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Virtus Equipment and ZERMA America: What Is the Difference?
Virtus Equipment and ZERMA America are sister companies that sell the same line of industrial granulators — low speed granulators, central granulators, heavy duty granulators, beside-the-press models, and pipe and profile granulators — under different brand names. Replacement granulator knives and wear parts are interchangeable across both brands for the same model series. This article explains the relationship between the two brands, what it means for parts sourcing, and how to identify your machine model to order the correct replacement knives.
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How to Set Granulator Knife Clearance Correctly
Knife clearance — the gap between the rotor knife edge and the stator bed knife at the point of closest approach — is one of the most important settings on any granulator. Too wide and you get oversized particles and higher motor load. Too tight and you risk knife-to-knife contact and catastrophic damage. This guide covers how to measure clearance, what the correct spec is for common Virtus Equipment and ZERMA America models, and how to adjust it after installing new rotor or stator knives.
Read Full ArticleEquipment Selection
Low Speed Granulator vs. High Speed Granulator: Which Do You Need?
Low speed granulators run at lower rotor RPM with higher torque — ideal for thick-walled parts, hard materials, and applications where dust and fines must be minimized. High speed granulators process thin-walled parts, film, and runners quickly with a finer regrind output. Choosing the wrong type leads to excessive fines, poor throughput, or premature knife wear. This article compares both types across material compatibility, output quality, noise, and energy consumption to help you specify the right machine.
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