What Tonnage is Ideal for Cookware Deep Drawing
Selecting the correct press tonnage is one of the most critical steps in the cookware deep drawing process. Using too little tonnage results in wrinkled, poorly formed pieces, while too much tonnage can damage the tooling, the press, and the material itself. The "ideal" tonnage is not a single number but a calculated range based on several key factors.
Key Factors That Determine Required Tonnage
Tonnage (the force exerted by a hydraulic press) directly correlates to the resistance of the material and the demands of shaping. The following factors are non-negotiable in calculations:
1. Material Type & Thickness
Different cookware materials have unique tensile strengths and plasticity, while thickness increases the force needed to deform the metal.
Aluminum: Soft and ductile, requiring lower tonnage. For 1–3mm thick aluminum (common in lightweight pots/pans), 100–315 tons suffice.
Stainless Steel: Harder (especially 18/10 grades) with higher tensile strength. 0.8–2mm thick stainless steel cookware typically needs 200–630 tons; larger frying pans may require 1000 tons.
Non-Stick Coated Metals: Coating adds minimal resistance, but tonnage follows the base material (e.g., 200–400 tons for coated aluminum).
Thickness is a primary driver: doubling material thickness can nearly double required tonnage.
2. Cookware Size & Drawing Depth
Larger diameters and deeper draws increase the surface area under force, raising tonnage needs:
Small Cookware: 15–20cm diameter (e.g., saucepans) with 5–10cm depth: 100–200 tons.
Medium Cookware: 25–30cm diameter (e.g., frying pans) with 10–15cm depth: 315–630 tons.
Large Cookware: 35cm+ diameter (e.g., stockpots) or 20cm+ depth: 800–1500 tons. Some extra-large stainless steel pots even use 2000–3000 ton presses.
3. Drawing Complexity & Process Stages
Single-Stage vs. Multi-Stage Drawing: Simple shallow draws (e.g., flat-bottomed pans) may use lower tonnage in one pass. Deep or shaped cookware (e.g., lidded pots with curved sides) requires multi-stage drawing—each stage needs tonnage, and intermediate annealing (to reduce material hardness) may lower coefficient values (thus slightly reducing force).
Die Design: Intricate dies (e.g., ridged sides or integrated handles) create more friction and resistance, increasing tonnage by 10–20% compared to smooth designs.
4. Safety & Operational Margins
Manufacturers universally add a 10–20% safety factor to calculated tonnage to account for variables like friction, material inconsistencies, and die wear. For example, if calculations show 400 tons are needed, a 450–500 ton press is preferred.
What Tonnage is Ideal for Cookware Deep Drawing
Empirical Tonnage Ranges by Cookware Type
Based on industry data, here are typical tonnage ranges for common cookware, organized by material and size:
Cookware Type Material Thickness Diameter Ideal Tonnage Range
Small saucepan (16cm) Aluminum 1–2mm 16cm 100–160 tons
Medium frying pan (26cm) Aluminum 2–3mm 26cm 200–315 tons
Small frying pan (22cm) Stainless Steel 0.8–1.2mm 22cm 200–400 tons
Large stockpot (36cm) Stainless Steel 1.5–2mm 36cm 800–1200 tons
Non-stick sauté pan (28cm) Coated Aluminum 2mm 28cm 315–500 tons
How to Calculate Exact Tonnage
For precision, use empirical formulas tailored to cylindrical cookware (the most common shape). Below is the industry-standard method for cylindrical parts :
Step 1: Calculate Maximum Deep Drawing Force
For the first drawing stage (most force-intensive):Pmax = π × dp × t × rm × k
● Pmax: Maximum drawing force (Newtons, N)
● π: 3.1416
● dp: Diameter of the cookware after drawing (mm)
● t: Blank thickness (mm)
● rm: Material tensile strength (MPa; e.g., aluminum = 90–120 MPa, stainless steel = 500–700 MPa)
● k: Coefficient (1.0–1.3 for first draws; higher for harder materials)
Step 2: Convert Force to Tons
Since 1 ton = 9806.65 N, divide Pmax by 9806.65 and add the 10–20% safety factor.
Example Calculation: 28cm Stainless Steel Frying Pan
● dp = 280mm, t = 1.2mm, rm = 600 MPa, k = 1.2
● Pmax = 3.1416 × 280 × 1.2 × 600 × 1.2 ≈ 725,760 N
● Tonnage (without safety factor) = 725,760 ÷ 9806.65 ≈ 74 tons
● Tonnage (with 20% safety factor) = 74 × 1.2 ≈ 89 tons
Note: This is a base calculation—multi-stage drawing or large depth would increase tonnage to 200–400 tons, aligning with industry practice.
Common Mistakes to Avoid
Under-Tonnaging: Leads to incomplete drawing, material tearing, or die damage. A 100-ton press for a 25cm stainless steel pan (requiring 200 tons) will fail to form the shape.
Over-Tonnaging: Wastes energy, accelerates press wear, and may distort the cookware. Using a 1000-ton press for a small aluminum saucepan is inefficient.
Ignoring Friction: Poorly lubricated dies or rough surfaces increase resistance—always account for this in coefficient selection.
Final Recommendations
Start with Material & Size: Use the table above as a baseline (e.g., 200–630 tons for most household stainless steel cookware).
Calculate Precisely: Use the Pmax formula for custom or high-volume production.
Consult Hydraulic Press Manufacturers: Suppliers like Delishi/Goodsjack can tailor tonnage to your cookware specs (e.g., 250 tons for small stainless pots, 3000 tons for extra-large vessels).
By aligning tonnage with these factors, you ensure consistent quality and cost-effective cookware production.
GOODSJACK HYDRAULIC MACHINERY CO., LTD
DELISHI MACHINERY TECHNOLOGY CO., LTD
Hydraulic Press Machine, Hydraulic Forging Press Manufacturer
Web: www.hydraulic-press-machine.com
www.goodsjack.com
Tel: +86-769-88057683 83223615
Fax: +86-769-83231691
Dongguan Factory General Factory : No3, Jinfu Road, Jinma Industrial Park, Liaobu Town, Dongguan, Guangdong, China
Branch Factory: No210 Heshi Road, Qiaotou Town, Dongguan, Guangdong, China
Hubei Factory
Address: Sanhua Industrial Park, Binjiang New Area, Huangshi, Hubei, China
Eva Lee Sales Manager
Email: sales@goodsjack.com
WhatsApp/Wechat:+ 86 13509801050
Alice Xu Sales Manager
Skype: alice.goodsjack
Email: sales1@goodsjack.com
WhatsApp/Wechat: +86 13642957273
Key Factors That Determine Required Tonnage
Tonnage (the force exerted by a hydraulic press) directly correlates to the resistance of the material and the demands of shaping. The following factors are non-negotiable in calculations:
1. Material Type & Thickness
Different cookware materials have unique tensile strengths and plasticity, while thickness increases the force needed to deform the metal.
Aluminum: Soft and ductile, requiring lower tonnage. For 1–3mm thick aluminum (common in lightweight pots/pans), 100–315 tons suffice.
Stainless Steel: Harder (especially 18/10 grades) with higher tensile strength. 0.8–2mm thick stainless steel cookware typically needs 200–630 tons; larger frying pans may require 1000 tons.
Non-Stick Coated Metals: Coating adds minimal resistance, but tonnage follows the base material (e.g., 200–400 tons for coated aluminum).
Thickness is a primary driver: doubling material thickness can nearly double required tonnage.
2. Cookware Size & Drawing Depth
Larger diameters and deeper draws increase the surface area under force, raising tonnage needs:
Small Cookware: 15–20cm diameter (e.g., saucepans) with 5–10cm depth: 100–200 tons.
Medium Cookware: 25–30cm diameter (e.g., frying pans) with 10–15cm depth: 315–630 tons.
Large Cookware: 35cm+ diameter (e.g., stockpots) or 20cm+ depth: 800–1500 tons. Some extra-large stainless steel pots even use 2000–3000 ton presses.
3. Drawing Complexity & Process Stages
Single-Stage vs. Multi-Stage Drawing: Simple shallow draws (e.g., flat-bottomed pans) may use lower tonnage in one pass. Deep or shaped cookware (e.g., lidded pots with curved sides) requires multi-stage drawing—each stage needs tonnage, and intermediate annealing (to reduce material hardness) may lower coefficient values (thus slightly reducing force).
Die Design: Intricate dies (e.g., ridged sides or integrated handles) create more friction and resistance, increasing tonnage by 10–20% compared to smooth designs.
4. Safety & Operational Margins
Manufacturers universally add a 10–20% safety factor to calculated tonnage to account for variables like friction, material inconsistencies, and die wear. For example, if calculations show 400 tons are needed, a 450–500 ton press is preferred.
Empirical Tonnage Ranges by Cookware Type
Based on industry data, here are typical tonnage ranges for common cookware, organized by material and size:
Cookware Type Material Thickness Diameter Ideal Tonnage Range
Small saucepan (16cm) Aluminum 1–2mm 16cm 100–160 tons
Medium frying pan (26cm) Aluminum 2–3mm 26cm 200–315 tons
Small frying pan (22cm) Stainless Steel 0.8–1.2mm 22cm 200–400 tons
Large stockpot (36cm) Stainless Steel 1.5–2mm 36cm 800–1200 tons
Non-stick sauté pan (28cm) Coated Aluminum 2mm 28cm 315–500 tons
How to Calculate Exact Tonnage
For precision, use empirical formulas tailored to cylindrical cookware (the most common shape). Below is the industry-standard method for cylindrical parts :
Step 1: Calculate Maximum Deep Drawing Force
For the first drawing stage (most force-intensive):Pmax = π × dp × t × rm × k
● Pmax: Maximum drawing force (Newtons, N)
● π: 3.1416
● dp: Diameter of the cookware after drawing (mm)
● t: Blank thickness (mm)
● rm: Material tensile strength (MPa; e.g., aluminum = 90–120 MPa, stainless steel = 500–700 MPa)
● k: Coefficient (1.0–1.3 for first draws; higher for harder materials)
Step 2: Convert Force to Tons
Since 1 ton = 9806.65 N, divide Pmax by 9806.65 and add the 10–20% safety factor.
Example Calculation: 28cm Stainless Steel Frying Pan
● dp = 280mm, t = 1.2mm, rm = 600 MPa, k = 1.2
● Pmax = 3.1416 × 280 × 1.2 × 600 × 1.2 ≈ 725,760 N
● Tonnage (without safety factor) = 725,760 ÷ 9806.65 ≈ 74 tons
● Tonnage (with 20% safety factor) = 74 × 1.2 ≈ 89 tons
Note: This is a base calculation—multi-stage drawing or large depth would increase tonnage to 200–400 tons, aligning with industry practice.
Common Mistakes to Avoid
Under-Tonnaging: Leads to incomplete drawing, material tearing, or die damage. A 100-ton press for a 25cm stainless steel pan (requiring 200 tons) will fail to form the shape.
Over-Tonnaging: Wastes energy, accelerates press wear, and may distort the cookware. Using a 1000-ton press for a small aluminum saucepan is inefficient.
Ignoring Friction: Poorly lubricated dies or rough surfaces increase resistance—always account for this in coefficient selection.
Final Recommendations
Start with Material & Size: Use the table above as a baseline (e.g., 200–630 tons for most household stainless steel cookware).
Calculate Precisely: Use the Pmax formula for custom or high-volume production.
Consult Hydraulic Press Manufacturers: Suppliers like Delishi/Goodsjack can tailor tonnage to your cookware specs (e.g., 250 tons for small stainless pots, 3000 tons for extra-large vessels).
By aligning tonnage with these factors, you ensure consistent quality and cost-effective cookware production.
GOODSJACK HYDRAULIC MACHINERY CO., LTD
DELISHI MACHINERY TECHNOLOGY CO., LTD
Hydraulic Press Machine, Hydraulic Forging Press Manufacturer
Web: www.hydraulic-press-machine.com
www.goodsjack.com
Tel: +86-769-88057683 83223615
Fax: +86-769-83231691
Dongguan Factory General Factory : No3, Jinfu Road, Jinma Industrial Park, Liaobu Town, Dongguan, Guangdong, China
Branch Factory: No210 Heshi Road, Qiaotou Town, Dongguan, Guangdong, China
Hubei Factory
Address: Sanhua Industrial Park, Binjiang New Area, Huangshi, Hubei, China
Eva Lee Sales Manager
Email: sales@goodsjack.com
WhatsApp/Wechat:+ 86 13509801050
Alice Xu Sales Manager
Skype: alice.goodsjack
Email: sales1@goodsjack.com
WhatsApp/Wechat: +86 13642957273
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