compare_materials

Compare 2-4 polymer materials side-by-side to evaluate processing, thermal, and mechanical properties. Identifies key differences between thermoplastics to support material selection decisions for injection molding.

Instructions

Compare 2-4 materials side-by-side. Returns a table of processing, thermal, and mechanical properties with key differences highlighted. Available materials: abs-generic, pp-homo, pp-copo, pa6, pa66, pa66-gf30, pc, pc-abs, pom, hdpe, ldpe, pmma, pbt, pbt-gf30, pet, ps, hips, tpu, san, asa, ppe-ps

Input Schema

TableJSON Schema

Name	Required	Description	Default
`materials`	Yes	List of material IDs to compare (e.g., ["abs-generic", "pc", "pa66-gf30"])

Implementation Reference

src/tools/compare-materials.ts:3-74 (handler)

Main compareMaterials function - takes materialIds array, validates input (2-4 materials), looks up materials, and generates a formatted comparison table with processing, thermal, and mechanical properties plus key differences analysis

export function compareMaterials(materialIds: string[]): string {
  if (materialIds.length < 2) {
    return 'Please provide at least 2 material IDs to compare.';
  }
  if (materialIds.length > 4) {
    return 'Maximum 4 materials can be compared at once. Please reduce the list.';
  }

  const results: { query: string; material: Material | null }[] = materialIds.map(id => {
    const matches = findMaterial(id);
    return { query: id, material: matches[0] ?? null };
  });

  const notFound = results.filter(r => !r.material);
  if (notFound.length > 0) {
    return [
      `Materials not found: ${notFound.map(r => `"${r.query}"`).join(', ')}`,
      '',
      'Use get_material_properties to list available material IDs.',
    ].join('\n');
  }

  const mats = results.map(r => r.material!);
  const lines: string[] = [];

  lines.push(`# Material Comparison: ${mats.map(m => m.name).join(' vs ')}\n`);

  // General info
  lines.push('## General');
  lines.push(row('Family', mats.map(m => m.family)));
  lines.push(row('Type', mats.map(m => m.type)));
  lines.push(row('Filler', mats.map(m => m.filler ? `${m.filler} (${m.filler_pct}%)` : '—')));

  // Processing window
  lines.push('\n## Processing Window');
  lines.push(row('Melt temp range', mats.map(m => `${m.processing.melt_temp_min_C}–${m.processing.melt_temp_max_C}°C`)));
  lines.push(row('Melt temp (rec)', mats.map(m => `${m.processing.melt_temp_recommended_C}°C`)));
  lines.push(row('Mold temp range', mats.map(m => `${m.processing.mold_temp_min_C}–${m.processing.mold_temp_max_C}°C`)));
  lines.push(row('Mold temp (rec)', mats.map(m => `${m.processing.mold_temp_recommended_C}°C`)));
  lines.push(row('Max shear rate', mats.map(m => `${m.processing.max_shear_rate_1_s} 1/s`)));
  lines.push(row('Drying', mats.map(m =>
    m.processing.drying_temp_C != null
      ? `${m.processing.drying_temp_C}°C / ${m.processing.drying_time_hr}h`
      : 'Not required'
  )));
  lines.push(row('Max residence', mats.map(m => `${m.processing.max_residence_time_min} min`)));

  // Thermal
  lines.push('\n## Thermal Properties');
  lines.push(row('Conductivity', mats.map(m => `${m.thermal.thermal_conductivity_W_mK} W/(m·K)`)));
  lines.push(row('Specific heat', mats.map(m => `${m.thermal.specific_heat_J_kgK} J/(kg·K)`)));
  lines.push(row('Density', mats.map(m => `${m.thermal.density_kg_m3} kg/m³`)));
  lines.push(row('Ejection temp', mats.map(m => `${m.thermal.ejection_temp_C}°C`)));
  lines.push(row('No-flow temp', mats.map(m => `${m.thermal.no_flow_temp_C}°C`)));

  // Mechanical
  lines.push('\n## Mechanical Properties');
  lines.push(row('Tensile strength', mats.map(m => `${m.mechanical.tensile_strength_MPa} MPa`)));
  lines.push(row('Flexural modulus', mats.map(m => `${m.mechanical.flexural_modulus_MPa} MPa`)));
  lines.push(row('Elongation', mats.map(m => `${m.mechanical.elongation_at_break_pct}%`)));
  lines.push(row('HDT @ 1.8 MPa', mats.map(m => `${m.mechanical.HDT_at_1_8MPa_C}°C`)));
  lines.push(row('Shrinkage', mats.map(m => `${m.mechanical.shrinkage_pct_min}–${m.mechanical.shrinkage_pct_max}%`)));

  // Key differences
  lines.push('\n## Key Differences');
  lines.push(...generateKeyDifferences(mats));

  lines.push('\n---');
  lines.push('*Data from MoldSim MCP material database. Verify against supplier datasheets for your specific grade.*');

  return lines.join('\n');
}

src/server.ts:79-88 (registration)

Tool registration for compare_materials using server.tool() with Zod schema validation - registers with MCP server

server.tool(
  'compare_materials',
  `Compare 2-4 materials side-by-side. Returns a table of processing, thermal, and mechanical properties with key differences highlighted. Available materials: ${listMaterials().map(m => m.id).join(', ')}`,
  {
    materials: z.array(z.string()).min(2).max(4).describe('List of material IDs to compare (e.g., ["abs-generic", "pc", "pa66-gf30"])'),
  },
  async ({ materials }) => ({
    content: [{ type: 'text', text: compareMaterials(materials) }],
  })
);

src/server.ts:82-84 (schema)

Zod input validation schema for compare_materials - validates materials array must have 2-4 string items

{
  materials: z.array(z.string()).min(2).max(4).describe('List of material IDs to compare (e.g., ["abs-generic", "pc", "pa66-gf30"])'),
},

src/knowledge/materials.ts:74-89 (helper)

Material interface/type definition used by compareMaterials - defines structure for material properties including processing, thermal, and mechanical data

export interface Material {
  id: string;
  name: string;
  family: string;
  type: 'amorphous' | 'semi-crystalline';
  filler?: string;
  filler_pct?: number;
  mfi_g_10min?: number;
  mfi_condition?: string;
  cross_wlf: CrossWLF;
  tait_pvt: TaitPVT;
  thermal: ThermalProperties;
  processing: ProcessingWindow;
  mechanical: MechanicalProperties;
  notes: string;
}

src/knowledge/materials.ts:1117-1135 (helper)

findMaterial helper function - searches material database by ID/name/family with scoring, returns array of matching Material objects

export function findMaterial(query: string): Material[] {
  const q = query.toLowerCase().replace(/[^a-z0-9]/g, '');
  if (!q) return [];

  const norm = (s: string) => s.toLowerCase().replace(/[^a-z0-9]/g, '');
  const scored = MATERIALS.map(m => {
    const id = norm(m.id);
    const name = norm(m.name);
    const family = norm(m.family);
    const filler = norm(m.filler ?? '');

    if (id === q) return { m, score: 100 };
    if (id.startsWith(q) || q.startsWith(id)) return { m, score: 80 };
    if (id.includes(q) || name.includes(q)) return { m, score: 60 };
    if (family === q) return { m, score: 50 };
    if (family.includes(q)) return { m, score: 30 };
    if (filler.length > 0 && filler.includes(q)) return { m, score: 20 };
    return { m, score: 0 };
  }).filter(({ score }) => score > 0);

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