Investment Casting Design Guidelines 1. Linear Tolerance (mm)   Dimensions (mm) ≤10 10～25 25～50 50～75 75～100 100～150 150～200 200～250 ＞250 Normal (mm) ±0.15 ±0.25 ±0.35 ±0.50 ±0.65 ±1.00 ±1.50 ±1.80 ±1.00% Premium (mm) ±0.10 ±0.15 ±0.25 ±0.40 ±0.50 ±0.75 ±1.00 ±1.20 ±0.60% (ISO 8062) STANDARD TOLERANCE FOR PRECISION CASTING Dimensions (mm) ≤10 10～25 25～63 63～100 100～160 160～250 250～400 400～630 ＞630 Normal (mm) ±0.74 ±0.82 ±1.00 ±1.10 ±1.20 ±1.40 ±1.60 ±1.80 ±1.00% Premium (mm) ±0.52 ±0.58 ±0.70 ±0.78 ±0.88 ±1.00 ±1.00 ±1.20 ±0.60%   2. Angle Tolerance Angle Type          Normal 1 2 2 Premium 0.5 1 1 Avoid the quick changes of casting structure, use fillet radius on internal angle when possible, which is no less than R0.3   3. Surface Roughness (Ra/um) Rough Castings Weight>5kg, Main Wall Thickness>12mm 3.2-6.3 The surface finish for the castings we can provide with are as the following. Blacking, zinc plating, chrome plating and nickel plating for the carbon steel and the low alloy steel castings Tumbling, hand dull polishing, mirror polishing, electrolytic polishing and passivation treatment for the stainless steel castings and sand blasting, including glass beed blasting, corundum-sand blasting and quartz-sand blasting for all the steel castings. Weight>5kg, Main Wall Thickness>12m m 1.6-3.2 Finished Castings 0.8-1.6     4. Limit Dimension for Cast Holes and Slots Items Hole Diameter(Ø mm) L / D Ø2～Ø3 L / D ≤ 1 Ø4～Ø7 L / D≤ 2 ≥Ø8 L / D ≤ 2.5 Ø2～Ø3 L / D ≤ 2 Ø4～Ø7 L / D≤ 4 ≥Ø8 L / D ≤ 5 5. Size and Weight Range   Items Max Min Best Outline Dimension(mm) 1000×300×300 20×10×10 ＜150×100×100 Weight (Kg) 40 0.015 0.2～5 Min. Wall Thickness(mm) ─ 1.0 5～15 6. Design advice: No sharp corners, No sharp edges, No aligned ribs √ ╳