Shenzhen hand plate factory share the basic principles of sheet metal parts process matters

The Metal Materials Commonly Used In The Hardware Parts We Often Use Include Stainless Steel, Copper, Aluminum, Zinc Alloy, Magnesium Alloy , Steel, Iron, Etc. Hardware Products Are Often Divided Into Cold Processing Hot Processing According To Different Processing Methods. Different Types Of Hardware Have Different Forming Methods. Cold Processing, Such As Sheet Metal Materials, Are Mainly Formed By Cold Stamping, Bending, Drawing Other Processes. Shenzhen Prototype Factory Hot Processing, Such As Casting Parts, Are Mainly Formed By Melting The Hardware Raw Materials Into Liquid Casting Them With Molds.

It Is Generally Believed That All Sheet Metal Materials With Uniform Thickness Are Collectively Referred To As Sheet Metal. Sheet Metal Materials Commonly Used By Shenzhen Prototype Factories Include Stainless Steel, Galvanized Steel, Tinplate, Copper, Aluminum, Iron, Etc.

❶Principle Of Uniform Product Thickness

Sheet Metal Is A Material With Uniform Thickness, Attention Should Be Paid To It During Structural Design, Especially In Places With Many Bends, Which Can Easily Cause Uneven Thickness.

❷The Principle Of Easy Flattening

Sheet Metal Products Are Made Of Sheet Materials. Before Processing, The Raw Materials Are Flat. Therefore, When Designing Sheet Metal Parts, All Bends Bevels Must Be Able To Be Unfolded On The Same Plane Cannot Interfere With Each Other. If The Sheet Metal Parts Are Designed Properly, They Will Interfere With Each Other After Unfolding.

❸Appropriate Selection Of Sheet Metal Thickness Principle

Sheet Metal Parts Have Various Thicknesses Ranging 0.03 To 4.00 Mm, But The Thicker The Sheet Metal, The More Difficult It Is To Process, The Larger The Processing Equipment Required, The Higher The Defect Rate. The Thickness Should Be Selected According To The Actual Function Of The Product. The Thinner The Better, Provided That The Strength Function Are Met. For Most Products, The Thickness Of Sheet Metal Parts Should Be Controlled Below 1.00 Mm.

❹Comply With Processing Technology Principles

Sheet Metal Products Must Conform To Processing Technology Be Easy To Manufacture. Products That Do Conform To Processing Technology Cannot Be Manufactured Are Considered Unqualified Designs.

The Following Shenzhen Prototype Factory Classifies Discusses The Process Requirements For Sheet Metal Product Design

Processability: The Difficulty Of The Product In Various Processing Processes Such As Punching, Bending, Etc.

Process Requirements: These Process Properties Should Be Met When Designing Sheet Metal Products.

The Basic Processing Methods Are: Punching, Bending, Stretching, Forming, Etc.

Ordinary Punching Structure Processability

Ordinary Punching: Currently The Most Widely Used

Precision Punching: Requires Precise Punching Dies High-Precision Punching Equipment. The Cost Is Higher Than Ordinary Punching Is Generally Used For More Precise Products.

(1) The Shape Of The Punched Part Should Be As Simple As Possible, Avoiding Slender Cantilevers Narrow Slots.

The Depth Width Of The Protruding Concave Parts Of The Punched Parts Should Generally Be Less Than 1.5/T (T Is The Material Thickness). At The Same Time, Narrow Long Incisions Overly Narrow Grooves Should Be Avoided In Order To Increase The Edge Strength Of The Corresponding Parts Of The Mold.

(2) The Shape Of The Punched Parts Should Minimize The Waste During Layout, Thereby Reducing The Waste Of Raw Materials

(3) The Shape Inner Hole Of The Punched Parts Should Avoid Sharp Corners.

(4) Holes Square Holes In Punched Parts

The Holes Of Punched Parts Are Preferably Round Holes. When Punching, The Diameter Of The Punch Cannot Be Too Small Due To The Strength Of The Punch, Otherwise The Punch Will Be Easily Damaged. The Minimum Punching Size Is Related To The Shape Of The Hole, The Mechanical Properties Of The Material The Thickness Of The Material. Table 1-1 Shows The Minimum Punching Size Of Commonly Used Materials, T Is The Thickness Of The Sheet Metal Material.

The Minimum Punching Size Is Generally Less Than 0.40 Mm. Holes Smaller Than 0.40 Mm Are Generally Processed By Other Methods, Such As Corrosion, Laser Drilling, Etc.

(5) The Spacing Between Punched Holes The Hole Margins.

(6) When Punching Bent Drawn Parts, A Certain Distance Should Be Maintained Between The Hole Wall The Straight Wall.

When Punching Holes In Stretched Products, A Certain Distance Should Be Maintained Between The Hole Wall The Straight Wall To Ensure The Shape Position Accuracy Of The Hole To Ensure The Strength Of The Mold.

(7) When Designing Sheet Metal Parts, Try To Avoid Designs With Notches Sharp Corners.

The Sharp Corners Of The Notch Will Make The Die Punch Sharp, Which Is Easy To Damage The Punch, Cracks Are Also Easy To Form At The Sharp Corners Of The Notch Of The Product.

Bending

The Principle Of Bending: It Refers To Making Straight Edges, Bevel Edges, Curves Other Shapes On Sheet Metal Parts, Such As Bending Sheet Metal Parts Into L-Shape, U-Shape, V-Shape, Etc.

Die Bending: Generally Used For Sheet Metal Products With Complex Shapes, Small Sizes High Output.

Bending By A Press Brake: Generally Used For Sheet Metal Products With Large Dimensions Small Batch Production.

(1) Minimum Bending Radius Of Sheet Metal Bending Parts

When The Material Is Bent, The Outer Layer Is Stretched The Inner Layer Is Compressed In The Fillet Area. When The Material Thickness Is Constant, The Smaller The Inner Fillet, The More Severe The Material Stretching Compression; When The Tensile Stress Of The Outer Fillet Exceeds The Ultimate Strength Of The Material, Cracks Breaks Will Occur; If The Bending Fillet Is Too Large, It Will Be Affected By Material Rebound, The Accuracy Shape Of The Product Cannot Be Guaranteed. The Minimum Bending Radius For Designing Bending Parts Can Refer To Table 1-2.

(2) Height Of Straight Edge Of The Bent Part

The Straight Edge Height Of The Bent Part Cannot Be Too Small, Otherwise It Will Be Difficult To Meet The Precision Requirements Of The Product.

If The Straight Edge Height Of The Bent Part Is Less Than The Minimum Straight Edge Height Design Due To Product Structure Requirements, A Shallow Groove Can Be Processed In The Bending Deformation Area Before Bending. The Disadvantage Of This Method Is That It Reduces The Strength Of The Product Is Suitable If The Sheet Metal Material Is Too Thin.

(3) Minimum Hole Edge Distance Of The Bent Part. 

There Are Two Ways To Process Holes On Bent Parts. One Is To Bend First Then Punch; The Other Is To Punch First Then Bend. The Design Of The Margins Of Bending First Then Punching Refers To The Requirements Of Punching Parts; When Punching First Then Bending, The Hole Should Be Outside The Deformation Zone Of The Bend, Otherwise It Will Cause Deformation Of The Hole Easy Cracking Of The Opening.

(4) When Bending The Adjacent Edge Close To The Rounded Corner, The Bending Edge Should Maintain A Certain Distance The Rounded Corner, The Distance L ≥ 0.5t, T Is The Thickness Of The Sheet Metal.

(5) Process Notch Design Of Bending Parts

If Only A Part Of An Edge Is Bent, In Order To Prevent Cracking Deformity, A Process Cut Should Be Designed. The Width Of The Process Cut Should Be Less Than 1.5t, The Depth Of The Process Notch Should Be Less Than 2.0t+R, T Is The Thickness Of The Sheet Metal.

(6) Design Of The Dead Edge Of The Bent Part.

The Dead Edge Of The Bent Part Refers To The Bending Surface Being Parallel To The Bottom Surface, Commonly Known As The Dead Edge. The Previous Process Of The Dead Edge Is To Bend The Bent Edge To A Certain Angle Then Dead Fit It.

The Length Of The Dead Edge Is Related To The Thickness Of The Material. Generally, The Minimum Length Of The Dead Edge Is L≥3.5t+R, T Is The Thickness Of The Sheet Metal Material R Is The Minimum Inner Bending Radius Of The Previous Process Before The Dead Edge.

(7) Process Hole Design Of Bending Parts

When Designing U-Shaped Bent Parts, The Two Bending Sides Should Be The Same Length To Avoid Product Deviation During Bending Produce Scrap. If The Structural Design Does Allow The Two Sides To Be The Same Length, In Order To Ensure The Accurate Positioning Of The Product In The Mold, Process Positioning Holes Should Be Added In Advance During The Design. Especially For Parts That Are Bent Multiple Times, Process Holes Must Be Designed As Positioning References To Reduce Cumulative Errors Ensure Product Quality.

Stretch

1. Meaning

Sheet Metal Parts Stretching: The Process Of Drawing Sheet Metal Parts Into Round, Square, Special-Shaped Shapes With Side Walls, Such As Aluminum Washbasins, Stainless Steel Cups, Etc.

 2. Precautions For Stretching Sheet Metal Parts 

(1) The Minimum Fillet Radius Between The Bottom Wall Of The Stretched Part Should Be Greater Than The Plate Thickness, That Is, R1>T; In Order To Make The Stretching Process Smoother, R1=(3~5)T Is Generally Taken, The Maximum Fillet Radius Should Be Less Than 8 Times The Plate Thickness, That Is, R1<8t.

(2) The Minimum Fillet Radius Between The Flange The Wall Of The Stretched Part Should Be Greater Than Twice The Thickness Of The Plate, That Is, R2>2t; In Order To Make The Stretching Process Smoother, R2=5t Is Generally Taken, The Maximum Fillet Radius Should Be Less Than 8 Times The Thickness Of The Plate, That Is, R1<8t.

(3) The Minimum Fillet Radius Between Two Adjacent Walls Of A Rectangular Stretched Part Should Be R3 ≥ 3t. In Order To Reduce The Number Of Stretching Times, R3 ≥ 1/5H Should Be Taken As Much As Possible So That The Stretching Can Be Completed In One Time.

(4) Due To The Different Stresses In Different Parts Of The Stretched Parts, The Thickness Of The Material Changes After Stretching. Generally, The Original Thickness Is Maintained In The Center Of The Bottom, The Material Becomes Thinner At The Bottom Corners, The Material Becomes Thicker Near The Flange At The Top; The Material Becomes Thicker At The Corners Around The Rectangular Stretched Parts. When Designing Stretched Products, It Is Clearly Stated On The Drawings That The External Dimensions The Internal External Dimensions Must Be Guaranteed, The Internal External Dimensions Cannot Be Marked At The Same Time.

(5) The Material Thickness Of The Drawn Part Generally Takes Into Account The Rule That The Upper Lower Wall Thicknesses Are Unequal During Process Deformation (I.E., Thicker On The Top Thinner On The Bottom). When A Round Flangeless Drawn Part Is Formed In One Step, The Ratio Of Height H To Diameter D Should Be Less Than Equal To 0.4. 

In General, When Designing A Drawn Part, Attention Should Be Paid To The Fact That The Shape Of The Drawn Part Should Be As Simple As Possible, The Appearance Should Be As Symmetrical As Possible, The Drawing Depth Should Be Too Large.