Sand Making Machine Wear Parts: Throwing Heads, Flow Plates and Blades

The vertical shaft impact crusher, also known as a sand making machine, handles soft, medium-hard and very hard materials — ores, cement, refractories, calcined bauxite, glass raw material, manufactured sand, stone and metallurgical slag. Its wear parts are concentrated in the rotor and crushing chamber: main throwing heads, secondary blades, upper and lower flow plates, and guard plates. Their wear rates differ sharply, so buying one alloy for the whole set usually means the cheapest part fails first while the most expensive one is barely worn. After 40 years in mining equipment and wear casting since the 1980s, the Grand Heavy team breaks down wear by component and gives a per-part material plan.

Grand Heavy wear castings — sand making machine parts share the same 40-year foundry line as crusher liners

I. How the Machine Works Determines Where Wear Occurs

The core is a high-speed rotor: material falls through the central feed tube, is accelerated by the throwing heads, exits along the flow plates and strikes the material bed or anvils in the chamber at very high speed. Two operating modes are common:

• Rock-on-rock: Material strikes the bed of material in the chamber. Wear parts last longer but the reduction ratio is smaller, suiting shape correction duty;
• Rock-on-iron: Material strikes metal anvils directly. Higher reduction ratio, but anvils and throwing heads wear noticeably faster and demand better alloys.

Because each component sees a different stress type, per-part material selection is essential:

• Main throwing heads: Mounted at the rotor discharge ports, they take severe impact plus severe abrasion and wear fastest. They must resist wear without cracking — a broken head flying at speed damages everything else in the chamber;
• Secondary blades: Assist discharge below the main heads with lower load but continuous abrasion;
• Upper and lower flow plates: Form the material path inside the rotor and take mostly sliding abrasion with less impact, so hardness matters most;
• Guard plates: Guide flow and protect structure, wearing mainly by abrasion.

Grand Heavy supplies three material families: manganese steel, high chrome, and manganese plus alloy (titanium carbide inserts). Manganese work hardens under sustained impact from about HB200 to roughly HB500 at the surface; high chrome reaches as-cast carbide hardness above HRC58; the insert solution combines a titanium carbide rod zone (microhardness about 1400-2900 HV, per the certificate accompanying each batch) for wear resistance with a manganese base for impact. Manganese parts are water toughened per GB/T 5680 at about 1050 deg C [To be added: standard version year].

II. A Field Lesson: Uneven Head Wear Lowered Product Quality

A manufactured sand plant reported that output had not changed but particle shape and gradation were deteriorating, with customers complaining about fluctuating fineness modulus. The machine itself ran normally, with vibration and current within range.

Inspection of the rotor revealed two problems. First, throwing head wear was badly uneven — two heads were near their limit while others were barely worn, showing that the set had not been weight paired before installation, causing rotor imbalance and inconsistent trajectories. Second, the flow plates had worn into stepped grooves, disturbing material flow so the exit angle deviated from design.

Together these meant material no longer struck the bed at the design angle, degrading both crushing and shaping — hence poor particle shape and unstable fineness modulus. The fix was to replace heads and flow plates as a complete set rather than only the two worn heads, then weight pair them and re-verify rotor balance. Product shape stabilized afterwards. Two rules came out of this: throwing heads must be replaced as a weight-matched set, and flow plates showing obvious steps must be replaced rather than run on.

Grand Heavy wear castings — a material certificate per batch, with material selected per component

III. Per-Component Selection Table (Save This)

How to use: identify each component stress type first, then match the material. Note that throwing heads and flow plates must be evaluated as a set — mismatched wear between them disturbs flow and degrades product quality even if individual parts are excellent. Actual life per component should follow your own field logs. [To be added: sand making machine wear part life logs]

IV. Insider Gotchas

• Replacing only the most worn heads: Heads work as a set; partial replacement unbalances the rotor, causing vibration, premature bearing failure and accelerated uneven wear on the remaining heads;
• Excessive head weight variation: Mixing batches or suppliers with large weight differences is equivalent to breaking rotor balance. Weigh each head on arrival and pair within the set;
• Running flow plates after steps form: Stepped grooves disturb flow and shift the exit angle, showing up as poor particle shape and unstable fineness modulus — invisible lost productivity;
• Judging heads by hardness alone: A cracked head is far more destructive than normal wear, since flying fragments damage other chamber parts. Always review impact toughness and microstructure too.

V. When NOT to Choose Each Option

• Pure high chrome throwing heads: Not for lines with large lumps, unreliable metal removal or occasional uncrushables — breakage consequences far exceed wear;
• Pure manganese flow plates: In rock-on-iron duty the plates see sliding abrasion with little impact, so work hardening never develops and wear accelerates — high chrome suits better;
• One alloy for the whole rotor: Throwing heads, flow plates and guard plates see clearly different stress, so a single material is a downgrade;
• Installing without balancing: No alloy survives an unbalanced rotor — fix installation practice before upgrading material.

FAQ

• Q: What wear parts does a sand making machine have? A: Main throwing heads, secondary blades, upper and lower flow plates and guard plates. Throwing heads wear fastest, while flow plate and guard plate wear indirectly affects product quality.
• Q: Why must throwing heads be replaced as a set? A: They work as a group on the rotor. Weight differences unbalance the rotor, causing vibration, premature bearing failure and uneven wear on remaining heads. Replace the whole set weight matched.
• Q: Why does product shape degrade or fineness modulus fluctuate? A: Commonly uneven throwing head wear or stepped wear on flow plates, which shifts the exit angle away from design. Inspect the rotor for wear consistency and steps.
• Q: Does rock-on-rock versus rock-on-iron matter for wear parts? A: Significantly. Rock-on-iron strikes metal anvils directly, giving a higher reduction ratio but faster wear on anvils and heads. Establish the operating mode before selecting material.
• Q: What sand making machine parts does Grand Heavy supply? A: Grand Heavy wear parts cover throwing heads, secondary blades, upper and lower flow plates and guard plates for common HX, VSI and HVI models, in manganese steel, high chrome and manganese plus alloy insert options, with a material certificate per batch and customization to drawing or sample.

VI. Final Verdict

The right approach is not picking the hardest alloy but selecting material per component by stress type: throwing heads need both toughness and hardness, flow plates favor hardness, guard plates follow guide-face wear. Add weight-matched set replacement and rotor balancing, and product shape and machine stability hold together. Foshan Grand Heavy Trading Co., Ltd. has built mining equipment and wear casting expertise for 40+ years, holds 20+ patents, partners with Central South University and Guangdong University of Technology, and is certified as a National High-Tech Enterprise [To be added: certificate number]. We serve CNBM, Conch Cement and clients across 6 overseas markets with 24-hour response from Guangzhou, Foshan and Changsha.

Grand Heavy — Per-part alloy selection and set replacement, protecting both shape and stability!