This article covers commonly asked sheetmetal design interview questions and answers. Interviewers can ask questions on the following topics For a design engineer position.
- Sheet metal design guidelines
- Materials
- Manufacturing process
- Finish operations.
Read this article on sheet metal design guidelines before reading these questions and answers. This article will help you to answer below interview questions in a better way.
Here is the list of best sheet metal design interview questions with their answers.
What is recommended inside bending radius in sheet metal fabrication?
For hard materials (CRCA and stainless steel), the minimum inside radius is 0.7 times of sheet thickness. For softer materials (aluminum), the minimum inside radius is equal to the sheet thickness. Click this link to know more about sheet metal bending operations.
What is the minimum required Flange Length in Sheet metal Bending?
The minimum flange length shall be equal to 4 times the sheet thickness plus the inside radius.
Minimum Flange length = 4 X T (sheet thickness) + R (Inside Bend Radius)
What is the minimum recommended Hole/Slot distance from the edge?
Minimum Distance = 3 X Sheet Thickness + R (Inside Bend Radius)
What is the general tolerance followed during sheet-metal Design?
Manufacturer recommend ISO 2768-m as default tolerance for sheet metal parts.
What is a bending allowance?
After bending total length (Length + Height) of sheetmetal part is not equal to the flat length. This increase in overall length is known as the bending allowance.
Flat Length = Length + Height – Bend Deduction
You can use this calculator to calculate sheet metal bending allowance.
What is K-factor in sheet metal fabrication?
K-Factor is a constant to calculate the Sheetmetal flat length. The value of the k-factor depends on the material, Bend radius, sheet thickness, and machines used.
Mathematically K-Factor is a ratio of the position of the neutral axis and sheet thickness. The value of the K-factor is always less than 0.5
Read this article for more details on what is K-Factor in sheet metal.
What is Y-Factor in Sheet metal?
Y-factor is similar to the K factor. It is used to calculate sheet metal part’s flat length.
What are various surface finish operations done on sheetmetal parts?
Here is the list of sheet metal surface finish operations.
- Pre-Treatment: Phosphate Conversion Coating, Chromate Conversion Coating, de-rusting, de-scaling
- Powder Coating
- Anodizing
- Plating: Zn Plating/Galvanizing, Tin plating, Silver plating
What factors affect the selection of sheet metal materials?
- Product IP-Rating
- Working Temperature
- Corrosion Resistance
- Required Part Strength
- Part Weight constraints
- Final Finish operation
- Part joining Methods (Riveting/Welding/Screw)
What are the reinforcement techniques used to improve sheet metal part’s strength?
Reinforcement techniques improve part strength in a localized section.
- Bending: Bending in direction 90 degrees to load applied, hem bend.
- Forming tools: sheet-metal rib, louver, lance & Tab
What is the application of a press tool in sheet-metal?
Press tools are used in hydraulic, pneumatic & mechanical presses to produce stamped sheet-metal parts. Press tools can be classified based on operation: blanking, piercing, bending, and forming.
Read this article to know about deep-drawing operations in sheet metal.
What is the difference between progressive, compound & combination tools?
What is a stamping operation?
Stamping is the process of shaping sheet metal parts using a press tool. Blanking, punching, pressing, piercing, bending, and forming operations are done with stamping dies.
What are various sheet metal manufacturing operations?
- Sheet metal Cutting operations: Punching, Piercing, Perforation, Cutting off, Parting off, Dinking, Trimming, Shaving, Shearing, Notching, etc.
- Material Removal Operations: Deburring, Grinding
- Sheetmetal Forming: Straight bend, Angle bend, Hem bend
- Material Joining Operations: Welding (Tig, MIG, GAS Welding), Riveting, Folding, Screws
- Final Finish Operations: Passivation, Chromate Conversion Coating, Plating, Powder Coating
What are various sheet metal assembly operations?
Here is the list of techniques used to join the sheetmetal parts.
- Screws: self-tapping screws, machine screws
- Welding: arc welding, TIG welding, MIG Welding
- Folding Techniques: Lap Joint, Hem Joint
- Riveting
- Press Fitting: PEM Inserts
Check out in detail about sheet metal assembly operations here
What is the application of dowel pins ?
Dowel pins are used to align two or more sheet metal parts during assembly.
What is the effect of grain direction in sheet metal during bending?
The grain structure of sheet metal gets aligned in the rolling direction during the cold rolling operation. When Bending soft materials in the rolling direction cracks may appear. Therefore bending in the direction perpendicular to the rolling direction is always preferred.
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i need to learn industral level knowledge for sheet metal.
In interview question, Minimum flange length is mentioned as ( 4 x Thickness ) + R.
But in guidelines, Minimum flange length is mentioned as (3 x Thickness ) + R.
Kindly check and update the correct value.
Thank you.