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Improving Dry Press Strength: How Binders and Lubricants Reduce Cracking and Breakage

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2026-06-10

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APPLICATION GUIDE BINDER + LUBRICANT DRY PRESS

A systematic technical guide for ceramic plants seeking to reduce dry-press losses through the synergistic use of organic/inorganic binders and internal/external lubricants — covering mechanism, selection, dosing, lab validation, and cost savings.

Quick Answer: Dry-press cracking and edge breakage are primarily caused by elastic after-effect — the expansion that occurs when the pressed part is ejected from the die, generating tensile stresses that exceed the weak inter-particle bond strength of the green body. The solution has two components: (1) a binder — such as organic polymeric FG-ZM01 series (Active Ingredient: 95–98%, Source: Goway TDS) or inorganic mineral ZG-302/303 — to strengthen particle-to-particle bonds; and (2) a lubricant to reduce inter-particle and particle-to-die friction, enabling more uniform density distribution and fewer internal stress concentrations. The optimal result comes from using both together at application-specific ratios determined through a five-point dose-response trial.

Key Facts at a Glance

20–50%
Typical dry MOR improvement from organic binder addition at 0.5–2.0% dosage (industry reference range; actual results depend on body composition and pressing parameters)
Elastic After-Effect
Root cause of most dry-press cracking: post-ejection expansion creates tensile stress exceeding green strength
Binder + Lubricant
Using both is essential — binder strengthens bonds, lubricant enables uniform compaction; neither alone delivers optimal results
Cost Savings
Reducing breakage from 3% to 1% in a 5,000 m²/day line can recover material and energy costs of several thousand USD/month

In This Guide

  1. Why Dry-Pressed Bodies Crack: Root Cause Analysis
  2. How Binders Strengthen the Green Body
  3. How Lubricants Improve Compaction Uniformity
  4. Binder + Lubricant Synergy: Why Both Are Needed
  5. Selection & Dosing Matrix
  6. Laboratory Validation Protocol
  7. Cost-Benefit Analysis: Estimating Your Return
  8. Troubleshooting Guide
  9. Frequently Asked Questions
  10. Get Your Dry-Press Optimization Plan

1. Why Dry-Pressed Bodies Crack: Root Cause Analysis

To solve dry-press cracking and edge breakage, you must first understand the physical forces at work during and immediately after pressing. Four interconnected factors determine whether a pressed body survives ejection and handling intact.

1.1 Elastic After-Effect: The Immediate Post-Ejection Killer

When a ceramic body powder is compressed in a die, the particles are forced into a denser arrangement. As the press ram retracts and the part is ejected, the compressed body undergoes elastic springback — it expands slightly as the stored elastic energy in deformed particles is released. If the green body's inter-particle bond strength is lower than the tensile stress generated by this expansion, the body cracks — most commonly at edges, corners, and thin sections where stress concentrates.

The magnitude of elastic after-effect depends on:

  • Particle shape: Angular, plate-like particles store more elastic energy during compaction than rounded particles and exhibit greater springback (industry-typical observation).
  • Pressing pressure: Higher pressure produces higher density — and higher stored elastic energy. This is why simply increasing pressing pressure can increase cracking in poorly bonded bodies.
  • Moisture content: Too little moisture → insufficient particle lubrication → higher friction → uneven compaction → localised stress concentrations. Too much moisture → hydrostatic pressure pockets → delamination upon ejection.

1.2 Particle Friction and Density Gradients

During pressing, friction between particles (internal friction) and between particles and the die wall (external friction) creates density gradients within the pressed body. The top of the part (closest to the moving punch) typically achieves higher density than the bottom, and the centre may be denser than edges if die-wall friction is significant. These density variations create differential springback upon ejection: regions that were more compressed expand more, generating internal shear stresses at density boundaries.

Density Gradient Formation (Conceptual)
ρ(h) = ρ₀ · exp(−kμh/D)
where ρ(h) = density at height h from punch face; ρ₀ = density at punch face; k = geometric factor; μ = inter-particle friction coefficient; D = part diameter/width. Higher friction (μ) → steeper density gradient → greater non-uniform springback → increased cracking risk. Adapted from ceramic pressing theory (Ref: Reed, Principles of Ceramics Processing).

Particle size distribution and shape also affect friction. Ball-milled powders with a narrow size distribution pack less efficiently than those with a well-controlled bimodal distribution. If the mill output is too coarse or too angular, internal friction increases significantly. See our Ball Mill Energy & Grinding Aids guide for a detailed discussion of particle size control.

1.3 Inadequate Inter-Particle Bonding

In a pressed body without binder, particles are held together only by weak van der Waals forces and, if moisture is present, liquid bridges. These forces are typically insufficient to resist the tensile stress of elastic after-effect in bodies with more than ~15–20% non-plastic content (industry-typical threshold). As the proportion of non-plastic materials — quartz, feldspar, calcined alumina, zirconium silicate — increases, the natural plasticity from clay minerals becomes insufficient, and a binder becomes essential.

1.4 Granule Quality and Flow into the Die

Dry-press bodies are typically produced via spray drying, which forms roughly spherical granules. If these granules are too hard, too soft, too variable in size, or poorly flowing, die filling becomes uneven — creating local variations in fill density that translate into density gradients after pressing. Granules that are too hard do not break down under pressing pressure, leaving inter-granular voids that act as crack initiation sites. Refer to our Improve Ceramic Green Strength: Binder Selection guide for the spray-dried granule quality framework. Slurry viscosity directly determines granule size distribution and moisture uniformity from the spray dryer — see our Reduce Ceramic Slurry Viscosity guide for viscosity control methodology upstream of the press.

🟡 Granules Too Hard

  • Granule survives pressing intact
  • Inter-granular voids remain → weak boundaries
  • Cracks propagate along granule boundaries
  • Surface appears "pebbly" after pressing
  • Fix: reduce binder in slurry; adjust spray-dryer temperature profile

🟠 Granules Too Soft / Friable

  • Granule breaks down into dust during die filling
  • Poor flow → uneven fill → density variation
  • Fines segregate → compositional gradients
  • Surface appears dusty; edges crumble
  • Fix: increase binder in slurry; check spray-dryer atomiser condition

2. How Binders Strengthen the Green Body

A binder transforms a loose assembly of particles into a coherent green body by forming solid bridges between particles after drying. The mechanism differs between organic and inorganic types, and each has distinct advantages for specific production scenarios.

2.1 Organic Polymeric Binders: The High-Strength Option

Organic polymeric binders — such as Ceramic Body Binder FG-ZM01 series — dissolve or disperse in the slurry water during milling. As the spray-dried granule or pressed body dries, the polymer precipitates onto particle surfaces and forms a continuous film that bridges adjacent particles. Upon complete drying, this film creates a strong adhesive bond.

FG-ZM01A
Organic Polymeric Binder — High Active
Active Ingredient: 95–98%
Inorganic Salt By-product: 3–8%
Unreacted Monomer: <2%
L.O.I: 50–55%
Source: Goway Technical Data Sheet
FG-ZM01D
Organic Polymeric Binder — Standard Grade
Active Ingredient: 90–95%
Inorganic Salt By-product: 5–8%
Unreacted Monomer: <2%
L.O.I: 50–55%
Source: Goway Technical Data Sheet
🔗

Film Formation & Solid Bridge Bonding

As the pressed body dries, the dissolved polymer precipitates and forms a thin adhesive film spanning particle-to-particle contact points. Upon complete drying, these films crystallise or vitrify into solid bridges. The high active content of FG-ZM01A (95–98%) means more polymer per unit dosage, producing a denser bridging network for the same addition rate (Source: Goway TDS, FG-ZM01A).

🔥

Clean Burnout During Firing

Organic binders decompose and volatilise completely during the early stages of firing (typically 300–500°C), leaving no inorganic residue that could affect fired colour or phase composition. The L.O.I of 50–55% (Source: Goway TDS, FG-ZM01A/D) confirms full organic content available for burnout without mineral ash concerns.

📏

Dosage Efficiency

Because organic binders form a continuous film rather than discrete particle bridges, they are typically effective at lower dosages (0.5–2.0% on dry body weight, industry-typical reference range) than inorganic alternatives. Higher active content → lower dosage for same effect → reduced additive cost per unit strength gain.

2.2 Inorganic Mineral Binders: The Cost-Effective Option

Inorganic binders — such as ZG-302 and ZG-303 — function through a different mechanism. These are fine-grained aluminosilicate materials that, when mixed into the body, fill inter-particle voids and develop weak cementitious bonds during drying. They do not burn out during firing but instead become permanent components of the fired ceramic body.

ZG-302
Inorganic Mineral Body Binder
SiO₂: 60–65%
Al₂O₃: 13–15%
Fe₂O₃: 1–2%
Na₂O: 1–2%
CaO: 1–2%
MgO: 2–3%
L.O.I: 7–8%
Source: Goway Technical Data Sheet
ZG-303
Inorganic Mineral Body Binder — High SiO₂
SiO₂: 65–70%
Al₂O₃: 14–16%
Fe₂O₃: 1–2%
Na₂O: 1–2%
CaO: 1–2%
MgO: 2–3%
L.O.I: 6–7%
Source: Goway Technical Data Sheet
🧱

Void-Filling & Micro-Aggregate Bonding

Fine inorganic particles (<10 µm typical) fill the interstitial spaces between larger body particles, increasing the total number of particle contacts and reducing the average pore size. During drying, dissolved species (Na⁺, Ca²⁺) from the binder surface precipitate at contact points, forming weak cementitious bridges. The Al₂O₃ content (ZG-302: 13–15%, ZG-303: 14–16%) contributes to the fired body's strength.

♻️

No Burnout — Permanent Body Component

Unlike organic binders, inorganic binders do not decompose during firing. Their oxides (SiO₂, Al₂O₃, CaO, MgO) integrate into the fired ceramic matrix. This means they contribute to fired strength as well as green strength, but may slightly alter the body's fired composition — important for colour-sensitive bodies where Fe₂O₃ content (1–2% in both ZG-302/303) must be considered.

💰

Higher Dosage, Lower Unit Cost

Inorganic binders are typically used at higher dosages (2–5% on dry body weight, industry-typical reference range) than organic binders, but their lower unit cost often results in a lower total additive cost — especially for high-volume production where moderate strength improvement is sufficient and fired-colour tolerance is higher.

2.3 Organic vs. Inorganic Binder: Selection Criteria

Criterion Organic Polymeric (FG-ZM01) Inorganic Mineral (ZG-302/303)
Green Strength per Unit Dosage High — continuous film bridging Moderate — discrete particle bridges
Typical Dosage Range 0.5–2.0% (industry reference) 2–5% (industry reference)
Effect on Fired Body None — complete burnout Contributes to fired composition (SiO₂, Al₂O₃)
Fired Colour Impact None Minor — Fe₂O₃ 1–2% may slightly shift white-body tone
Best For White-body porcelain tile, thin large-format tile, colour-critical applications Red-body tile, high-volume standard production, bodies with high non-plastic content
Cost Profile Higher unit cost, lower dosage Lower unit cost, higher dosage

Dosage ranges are industry-typical reference values. Actual optimum dosage must be determined through a five-point dose-response trial using your specific body formulation and pressing parameters. FG-ZM01A/D specifications from Goway Technical Data Sheet. ZG-302/303 specifications from Goway Technical Data Sheet.

3. How Lubricants Improve Compaction Uniformity

While binders strengthen the bonds formed during pressing, lubricants ensure those bonds form uniformly throughout the body. A lubricant's primary role is not to add strength — it is to enable the binder to do its job by reducing the friction that prevents even compaction.

3.1 Internal vs. External Lubrication

Internal Lubricants

Mixed into the body powder before pressing. They adsorb onto particle surfaces and reduce inter-particle friction during compaction.

  • Examples: Polyethylene glycol (PEG), metal stearates (Mg/Ca/Zn), polyvinyl alcohol (PVA)
  • Mechanism: Form a thin lubricating film on particle surfaces; the polar end of the molecule adsorbs onto the oxide surface while the non-polar tail creates a low-friction interface
  • Typical dosage: 0.1–0.5% on dry body weight (industry-typical reference range)
  • Effect: Reduces the density gradient through the pressed part; enables particles to slide past each other into denser packing arrangements
  • Caveat: Over-dosing can coat particles too thoroughly, interfering with binder adhesion — this is why binder+lubricant ratio matters

External Lubricants

Applied to die walls and punch faces before each pressing cycle. They reduce die-wall friction and ejection force.

  • Examples: Magnesium stearate, zinc stearate, stearic acid (applied as spray, suspension, or dry film)
  • Mechanism: Create a low-shear boundary layer between the compacted body and the tool steel surface
  • Typical usage: Minimal quantity per cycle — applied as needed, not measured as percentage of body weight
  • Effect: Reduces ejection force; minimises die wear; improves surface finish of the pressed part (fewer drag marks)
  • Caveat: Over-application can leave residue on the green body surface that interferes with glazing adhesion
⚠ Data Gap Notice: The current v2.1 Goway product database does not contain lubricant-specific products. All lubricant dosage ranges, performance characteristics, and product-type recommendations in this section are drawn from industry-typical reference values and ceramic processing textbooks (e.g., Reed, Principles of Ceramics Processing; ASTM C133-97). For product-specific lubricant recommendations, please contact Goway technical support through the inquiry form at the end of this guide.

3.2 How Lubricants Indirectly Improve Green Strength

A lubricant does not directly strengthen the green body — but it creates the conditions under which a binder can perform optimally. The chain of causation is:

Lubricant → Strength Pathway
Lubricant reduces inter-particle friction
→ More uniform particle rearrangement during compaction
→ Reduced density gradients through the pressed body
→ More uniform springback upon ejection
→ Fewer internal stress concentrations
→ Lower probability of crack initiation
→ Higher effective green strength (fewer failures at a given average strength)
This means the binder's bond strength is utilised more efficiently. A lubricated body with a given binder dosage will have fewer crack-initiation sites than an unlubricated body with the same binder — and therefore lower breakage rate in production.

4. Binder + Lubricant Synergy: Why Both Are Needed

The single most important concept in dry-press strength optimisation is that binder and lubricant address different stages of the failure chain:

Stage Action Without Binder Without Lubricant With Both
1. Die Filling Granules flow into die cavity OK — granule flow depends on shape, not binder OK OK
2. Compaction Particles rearrange under pressure Weakly bonded contacts begin forming ❌ High friction → poor rearrangement → density gradients ✅ Low friction → uniform rearrangement
3. Pressure Hold Stress relaxes, bonds strengthen Limited bond formation — weak overall Stress not fully transmitted to all regions ✅ Stress evenly distributed → bonds form uniformly
4. Ejection Part exits die; elastic after-effect begins ❌ Weak bonds fail under springback tensile stress Lower ejection force, but bonds still weak ✅ Strong, uniform bonds resist springback
5. Handling / Transport Mechanical loads applied to green body ❌ Very fragile — high handling losses Some density uniformity, but overall fragile ✅ Significantly reduced handling losses

Qualitative description based on ceramic pressing theory. Actual performance depends on body composition, pressing parameters, and additive quality.

4.1 The Binder-to-Lubricant Ratio Principle

There is an optimal binder-to-lubricant ratio for each body formulation. The general principle:

  • Too much lubricant relative to binder: Particle surfaces become excessively coated, preventing the binder from forming strong bridges. Result: well-compacted but weakly bonded body — low green strength despite good density.
  • Too much binder relative to lubricant: The binder may form strong local bonds, but uneven compaction leaves internal stress concentrations and voids. Result: high local strength in dense regions, but cracking initiates in under-compacted regions.
  • Optimal ratio (application-dependent): Typically in the range of binder:lubricant = 3:1 to 8:1 by weight (industry-typical reference range). For example: 1.0% binder + 0.2% internal lubricant. This ratio must be determined experimentally for each body.

5. Selection & Dosing Matrix

5.1 Binder Selection Decision Table

Production Scenario Recommended Binder Type Starting Dosage Key Consideration
White-body porcelain tile, thin (<8 mm) FG-ZM01A (Organic, High Active) 0.5–1.0% Colour neutrality critical; high active content maximises strength per unit dosage
Large-format porcelain (≥ 900 × 900 mm) FG-ZM01A + internal lubricant 1.0–2.0% (binder) + 0.2–0.3% (lubricant) Large format = high absolute springback; requires both maximum bond strength AND uniform compaction
Red-body floor tile, standard format ZG-302 or ZG-303 (Inorganic) 2.0–4.0% Cost-sensitive; Fe₂O₃ from binder not a concern for red-body
High non-plastic body (>50% feldspar/quartz) FG-ZM01D + ZG-302 (Hybrid) 0.8–1.5% organic + 2.0–3.0% inorganic Hybrid approach: organic for strength points, inorganic for cost efficiency and void filling
Fast-cycle pressing (<5 cycles/min) FG-ZM01A + external lubricant 0.8–1.5% (binder) + external as needed Fast cycles increase die-wall friction heat; external lubricant essential for consistent ejection
Standard production, moderate breakage (2–4%) FG-ZM01D (Organic, Standard) 0.5–1.5% Balance of cost and performance; FG-ZM01D (Active: 90–95%) offers strong price-performance ratio
Body with recycled content (>30% fired scrap) FG-ZM01A + increased dosage 1.5–2.5% Recycled fired scrap has zero plasticity; needs higher binder dosage to compensate

Starting dosages are on dry body weight basis. All figures are starting points for laboratory dose-response trials — actual optimum depends on your specific body composition, pressing pressure, and moisture content. FG-ZM01A/D specifications from Goway Technical Data Sheet. ZG-302/303 specifications from Goway Technical Data Sheet. Lubricant dosage ranges are industry-typical reference values.

5.2 Lubricant Selection by Application

Application Need Lubricant Type Typical Starting Dosage Notes
Improve compaction uniformity Internal — PEG, metal stearate 0.1–0.3% Start low; over-dosing interferes with binder bonding. Industry-typical reference range.
Reduce ejection force External — Mg stearate spray As needed per cycle Apply thin even film; over-application causes glazing defects. Industry-typical practice.
Reduce die wear External — Zn stearate As needed per cycle Zn stearate offers higher-temperature stability for fast-cycle pressing. Industry-typical practice.
Improve surface finish Internal — PVA (low MW) 0.05–0.15% PVA adds some binding as well as lubrication at low dosages. Industry-typical reference range.

Lubricant types and dosage ranges are industry-typical reference values from ceramic processing literature. Actual selection and dosage must be validated for your specific body and press conditions. Goway product-specific lubricant recommendations are available through technical consultation.

6. Laboratory Validation Protocol

Before implementing binder and lubricant changes on a production line, run this seven-step laboratory protocol to quantify the effect and establish the optimum dosage for your specific body.

1

Prepare Baseline Body

Prepare 5 kg of your standard production body powder — same composition, same moisture content, same spray-dried granule properties — to serve as the control. Press 10 test bars (recommended: 120 × 25 × 8 mm or your standard test geometry) at your normal production pressing pressure. Measure density (Archimedes or geometric), weigh each bar, and record pressing conditions. These are your Baseline (B) specimens.

2

Prepare Binder Dose-Response Series

From your production body powder, prepare five sub-batches with binder additions at D1=0.5%, D2=1.0%, D3=1.5%, D4=2.0%, D5=2.5% (dry weight basis). Mix thoroughly — for small batches, a laboratory V-blender or Turbula mixer for 10–15 minutes ensures homogeneous distribution. Press 10 bars per dosage level at the same pressing pressure as Baseline.

3

Add Lubricant (If Testing Synergy)

If the goal is binder+lubricant synergy, prepare a second dose-response series at the same binder levels but with a fixed lubricant addition (recommended starting point: 0.2% PEG or equivalent internal lubricant). This gives you a 5×2 matrix (5 binder levels × 2 lubricant conditions: with/without). Press 10 bars per condition.

4

Dry Under Controlled Conditions

All pressed specimens must be dried under identical conditions to eliminate moisture-content variation as a confounding variable. Recommended: 110°C in a laboratory oven for 2 hours, then cool to room temperature in a desiccator before testing. Weigh each dry specimen to verify moisture loss.

5

Measure Dry MOR (ASTM C133-97 or Equivalent)

Test dry modulus of rupture (MOR) using a three-point bending fixture (Ref: ASTM C133-97, Standard Test Methods for Cold Crushing Strength and Modulus of Rupture of Refractories, commonly adapted for ceramic green bodies). Span: 100 mm for a 120 mm bar. Crosshead speed: 0.5 mm/min. Record breaking load and calculate MOR: MOR = 3FL / 2bd² where F = breaking load, L = span, b = width, d = thickness. Test all 10 specimens per condition; report mean ± standard deviation.

6

Plot Dose-Response Curve

Plot Mean Dry MOR (y-axis) vs. Binder Dosage (x-axis), with separate curves for with-lubricant and without-lubricant conditions. Identify: (a) the dosage at which MOR gain begins to plateau (law of diminishing returns), and (b) the dosage at which the with-lubricant curve separates most clearly from the without-lubricant curve (synergy window). The optimum commercial dosage is typically at or just past the inflection point of the curve — where incremental benefit per unit dosage begins to decline.

7

Validate on Production Press (Pilot Batch)

Scale the optimum laboratory dosage to a full production batch. Press 500–1,000 pieces under normal production conditions. Track breakage rate from pressing through firing. Compare against historical breakage data for the same product. Run for a minimum of one full shift. Also evaluate: fired colour (ΔE vs. standard), fired water absorption, and glaze adhesion — to confirm the binder/lubricant does not introduce firing or glazing side effects.

ASTM C133-97 is the standard reference for MOR testing of refractory ceramics. For porcelain tile bodies, adaptations of this method are standard industry practice. All dosage levels are starting points — adjust based on your specific body composition.

Testing Checklist

Parameter to Record Why It Matters When to Record
Body moisture content (%) Moisture significantly affects green strength; must be controlled to isolate binder effect Before pressing — for each test condition
Pressing pressure (MPa / bar) Pressure affects density, which affects green strength non-linearly During pressing — record for every specimen
Green density (g/cm³) Correlates with MOR; confirms consistent pressing After pressing — for every specimen
Ejection force (if measurable) Indicates lubricant effectiveness; trend should decrease with lubricant addition During pressing — record when press instrumentation allows
Dry weight after oven drying Confirms consistent moisture removal After drying — for every specimen
Dry MOR (MPa) — mean ± SD Primary outcome measure After drying — 10 specimens per condition
Visual inspection: cracks, delamination Qualitative but essential — some failures are not captured by MOR After pressing, after drying, after firing

7. Cost-Benefit Analysis: Estimating Your Return

Binder and lubricant additions increase raw material cost per square metre. The question is whether the savings from reduced breakage and improved line efficiency exceed that cost. Here is a framework for your own calculation.

7.1 Cost-Benefit Calculation Model

📊 Breakage Reduction Savings Calculator

Input your plant's actual figures for a personalised estimate. Values below are illustrative.

Daily production (m²)5,000
Current breakage rate (pressing + drying + handling)3.0%
Target breakage rate (with binder + lubricant)1.0%
Square metres saved per day5,000 × (3.0% − 1.0%) = 100 m²/day
Raw material + energy cost per m² (indicative)Refer to plant accounting
Cost of re-working scrapped materialCrushing + re-milling + re-spray drying energy
Press downtime from die cleaning (hr/month)Loss of production capacity
Handling labour for scrapped piecesLabour cost allocation
Cost of binder additive (e.g., 1.0% FG-ZM01D)
Cost of lubricant additive (e.g., 0.2% PEG)
Net Savings = (Breakage savings) − (Additive costs)Calculate for your plant

7.2 Hidden Savings Beyond Breakage

Beyond the direct cost of scrapped product, binder and lubricant optimisation delivers savings that are harder to quantify but often larger:

Hidden Cost Category How Binder + Lubricant Reduce It Typical Magnitude
Die Wear External lubricant reduces die-wall friction → extends die life between re-grinds Die life extension may be 20–50% (industry-typical estimate based on reduced friction). Actual depends on tool steel grade and pressing cycles.
Press Downtime Fewer die-sticking events → fewer stops for cleaning; faster ejection → fewer jammed cycles Each 5-minute cleaning stop on a line producing 30 cycles/min = 150 lost pressings. If happening 3×/shift, that is 450 lost pressings/shift.
Handling Labour Higher green strength → less careful handling required → faster line speeds; fewer broken pieces to remove from the line Difficult to generalise; track "pieces handled per operator-hour" before and after implementation.
Firing Yield Improvement Fewer micro-cracks created during pressing → fewer firing failures (cracks propagate during sintering) Micro-cracks not visible in green state can propagate during firing. Reducing green-state micro-cracks may improve firing yield by 0.5–2.0 percentage points (industry-typical observational data).
Energy for Re-work Every broken piece that is crushed, re-milled, and re-spray-dried consumes energy. Lower breakage → less re-work energy. Spray drying is one of the most energy-intensive unit operations. See Spray Drying Energy Optimization (visit /News_detail/155.html) for a framework to quantify re-work energy cost.

8. Troubleshooting Guide

🟡 Binder not improving strength as expected
Possible causes: (1) Binder not properly dispersed during milling — check mixing time. (2) Binder dosage too low for body's non-plastic content. (3) Moisture content too low — binder requires some moisture to activate film formation. (4) Lubricant over-dosing — lubricant coating particles prevents binder adhesion.
Action: Run the five-point dose-response protocol (§6). If the dose-response curve is flat, investigate mixing, moisture, and lubricant interaction. If the curve rises but plateaus below target, switch to a higher-active binder (e.g., FG-ZM01A vs. FG-ZM01D) or consider a hybrid organic+inorganic approach.
🟠 Edge breakage persists despite binder addition
Possible causes: (1) Die-wall friction causing density gradients — edges are under-compacted. (2) Die design issue — sharp corners create stress concentrations. (3) Ejection speed too high.
Action: Add external lubricant to reduce die-wall friction. Check die condition for wear or galling. If edges are visibly lower density than centre (colour/appearance difference), the density gradient is the problem — solve with lubrication, not more binder.
🟡 Lamination / horizontal cracking
Possible causes: (1) Air entrapment — pressing too fast; air cannot escape. (2) Over-pressing — excessive pressure traps air and creates elastic rebound layers. (3) Granules too hard — do not deform adequately under pressure.
Action: Reduce pressing speed; add a decompression step in the pressing cycle; check granule hardness (should deform but not shatter under thumb pressure). Ensure granule moisture is within 5–7% range (industry-typical for porcelain tile spray-dried powder).
🟠 Glaze adhesion problems after binder change
Possible causes: (1) External lubricant residue on green body surface. (2) Organic binder creates a surface film that repels water-based glaze. (3) Green body absorbs glaze water differently with new binder.
Action: Reduce external lubricant application. If using organic binder at the high end of the dosage range (≥2.0%), test glaze water absorption time on the green body — compare with baseline. A slight increase in absorption time is normal; significant increase requires adjusting glaze rheology or reducing binder dosage.
🟡 Fired colour shift after binder addition
Possible causes: (1) Inorganic binder (ZG-302/303) introduces Fe₂O₃ (1–2%) into the body, which may shift white-body tone. (2) Organic binder burnout incomplete — residual carbon trapped if firing cycle too fast.
Action: For colour-critical white-body production, use organic binder (FG-ZM01A/D) which burns out completely with no residue. If using inorganic binder, measure ΔE on fired tiles vs. baseline. Ensure firing cycle has adequate oxidation hold at 350–500°C for complete organic burnout.

9. Frequently Asked Questions

Q: What is the most common cause of dry-press cracking?
Elastic after-effect — the expansion that occurs when the pressed part is ejected from the die — is the primary mechanism. If the green body's inter-particle bond strength is lower than the tensile stress from springback, cracking occurs, typically at edges and corners where stress concentrates. This is why binder addition (to strengthen bonds) and lubrication (to reduce uneven springback from density gradients) are complementary solutions.
Q: How much dry strength improvement can I realistically expect?
Industry experience indicates that adding 0.5–2.0% organic polymeric binder can improve dry MOR by 20–50% relative to an unmodified body, depending on the base body's non-plastic content, moisture level, and pressing parameters. These are industry-typical reference ranges; actual improvement must be determined through laboratory dose-response trials with your specific body formulation.
Q: Should I use organic or inorganic binder?
The choice depends on your production priorities. Organic binders (FG-ZM01 series, Active Ingredient: 90–98%, Source: Goway TDS) provide the highest strength per unit dosage, burn out completely without affecting fired colour, and are preferred for white-body and large-format tile. Inorganic binders (ZG-302/303) are more cost-effective for high-volume standard production where moderate strength improvement is sufficient and fired colour is less critical (red-body). A hybrid approach — organic for strength peaks, inorganic for cost efficiency — is common in many plants.
Q: Do I need lubricant if I already use a binder?
In most cases, yes. A binder strengthens inter-particle bonds; a lubricant enables those bonds to form uniformly throughout the body by reducing friction during compaction. Without lubricant, density gradients develop during pressing (top denser than bottom, centre denser than edges), creating differential springback and internal stress concentrations upon ejection. The binder may produce strong local bonds in dense regions, but cracks will initiate in under-compacted regions. Adding lubricant — especially in bodies with high non-plastic content or large tile formats — is usually the most cost-effective next step after binder optimisation.
Q: What is the risk of over-dosing lubricant?
Over-dosing internal lubricant (typically above 0.5% on dry weight) can coat particle surfaces too thoroughly, interfering with the binder's ability to form strong adhesive bridges between particles. The result is a well-compacted body with weak inter-particle bonding — counterintuitively, excessive lubrication reduces green strength. Always run a dose-response trial with your specific binder+lubricant combination to identify the point of diminishing returns or negative interaction.
Q: How long does it take to see ROI from binder/lubricant implementation?
The most immediate return is visible within days: reduced press downtime from die cleaning and reduced green-state breakage (count broken pieces per shift before and after). Full ROI accounting — including die life extension, reduced re-work energy, and improved firing yield — may take 1–2 months of data collection to quantify. We recommend running a 4-week pilot with detailed breakage tracking (by shift, by product, by cause) to build a complete business case.

10. Get Your Dry-Press Strength Optimisation Plan

Request Your Free Dry-Press Diagnostic & Additive Recommendation

Submit your production details below and our technical team will provide a customised binder + lubricant recommendation — including suggested starting dosages, compatibility assessment with your body formulation, and sample arrangement for laboratory validation.

Request Your Dry-Press Diagnostic →

To submit your production details and receive a customised recommendation, visit the Ceramic Body Binder FG-ZM01 product page and use the inquiry form. Please reference this guide ("Improving Dry Press Strength") when submitting.

Body Composition
Clay types and proportions; non-plastic content (feldspar, quartz, talc, etc.); any recycled material content; typical moisture after spray drying
Pressing Parameters
Press tonnage and type; cycle rate (cycles/min); typical pressing pressure; tile format and thickness; die condition
Current Breakage Data
Approximate breakage rate (%); where in the process (after press, after dryer, handling, firing); failure mode (edge, corner, lamination)
Target Improvement
Target breakage reduction; any constraints (colour sensitivity, cost targets, existing additive contracts); production volume (m²/day)

To submit an inquiry, visit our Ceramic Body Binder FG-ZM01 product page and use the inquiry form. Please reference this guide ("Improving Dry Press Strength") when submitting.

Author & Technical Authority

Goway Chemical Co., Ltd. — Guangdong Province, China. ISO 9001 certified manufacturer of ceramic additives with over 15 years of industry experience and an annual production capacity of 30,000 metric tons. Goway was the first automated solid deflocculant manufacturer in Guangdong. Products comply with REACH regulations for export markets.

Disclaimer: The information in this guide is based on Goway Technical Data Sheets (FG-ZM01A, FG-ZM01D, ZG-302, ZG-303), industry-typical reference values from ceramic processing literature, and accumulated application experience. All recommended starting dosages must be validated through laboratory and production-line trials with the user's specific body composition and pressing parameters. Final process parameters should be verified against the latest batch Certificate of Analysis. Goway Chemical does not guarantee specific performance outcomes without prior laboratory validation under the user's conditions.

Related Resources

  • Ceramic Body Binder FG-ZM01 — FG-ZM01A (Active: 95–98%) and FG-ZM01D (Active: 90–95%) full specifications and application guidance (visit /products_detail/12.html)
  • Improve Ceramic Green Strength: Binder Selection — complementary guide on green strength optimisation including spray-dried granule quality (visit /News_detail/158.html)
  • Spray Drying Energy Optimization — energy cost framework for quantifying re-work savings (visit /News_detail/155.html)
  • Reduce Ceramic Slurry Viscosity — slurry preparation affects granule quality, which affects dry-press performance (visit /News_detail/150.html)
  • Ball Mill Energy & Grinding Aids — particle size control for optimal pressing behaviour (visit /News_detail/156.html)

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GOWAY INTERNATIONAL MATERIAL CO., LTD

Founded in 2009, we specialize in producing and supplying ,ceramic additives and related products, committing to supplying stable, environmentally friendly,professional and ceramic materials.

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Company Phone/Wechat：86-0757-82131106 / +8613728575572
Company Fax：86-0757-82131106
Whatapp/skype: +8613600032377
E-mail：info6@goway-china.com
Office Address: Room C11-6, Foshan National Torch Innovation and Pioneer Park, Jihua 2nd Road, Chancheng District, Foshan City, Guangdong Province, China.
Factory Address: Nanbian Industrial Zone, Sanshui District, Foshan City Guangdong Province，China.

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