This article covers commonly asked sheet metal design interview questions and answers. For a design engineer position. Interviewers can ask questions on sheet metal design guidelines, materials, manufacturing process, and finish operations. We suggest you read this article on sheetmetal design guidelines before reading these questions and answers.
Here are the commonly asked sheet metal design interview questions with answers.
What is the difference between sheetmetal blanking, punching & piercing operation?
Blanking is a process in which the punch operation removes a final product from a larger piece of sheet metal.
Punching is a material removal process in which the punch operation removes material from a final piece of sheet metal.
Piercing is a process in which punch operation cuts a hole/material by tearing operation from a final piece of sheet metal. Piercing is a blanking operation
What are the various steps to manufacture sheet metal parts?
Here are the steps followed to manufacture sheet metal part using press bending:
Step-1: Flat pattern calculations. Use this calculator to calculate the flat pattern of the sheet metal parts.
Step-2: CNC Punching Process Programming.
Step-3: Cutting operations. It includes CNC Punching, laser, or water cutting, etc.
Step-4: Deburring
Step-5: Hardware assembly ( PEM Hardware, Weld Nut, Rivet hardware)
Step-6: Press Bending
Step-7: Joining operations (welding/riveting)
Step-8: Grinding
Step-9: Finish operations such as anodizing, plating, powder coating
Step-10: Packing
What are various sheet metal materials?
Following are the common materials used for sheet metal manufacturing.
- CRCA
- HRCA
- Aluminum
- Galvanised Iron (GI)
- Stainless Steel
Click this link!! For more details on sheet metal materials.
What is the difference between hot rolled & cold rolled steel sheets?
The hot rolling process involves steel rolling above re-crystallization temp. During the cooling process, steel will shrink. Therefore the size and shape of the steel will be less predictable.
Whereas cold rolling involves steel rolling below re-crystallization temp (at room temp). Refer to this article for more details on the difference between hot and cold rolled steel.
What are Sheet Metal Joining Operations?
Sheet metal Joining Operations can be classified into two categories.
A) Permanent Joints:
- Welding
- Adhesive Bonding
- Riveting
- Clinching
B) Reusable Joints:
- Metric Screws
- Self Cutting Screws
- Sheet metal tabs
- Hemming
What are various sheetmetal cutting operations?
- Shearing
- Punching
- Blanking
- Nibbling
- Perforation
- Trimming
- Deburring
Why punching is preferred over the laser cutting process?
Sheet metal forming operations such as a extruded hole, lancing, cut and bend are not feasible with laser cutting.
What is the minimum possible hole diameter using sheet metal turret punching press?
The minimum diameter of the hole that can be punched in sheet metal should be equal to sheet thickness.
What are various press bending operations on sheet metal parts?
- 90-degree bend
- Z bend
- Hem bend
- Tab Bend
What are various welding operations done on sheet metal parts ?
- TIG welding
- MIG Welding
- Gas Welding
- Spot welding
- Seam welding
Refer this article for more details on various welding techniques.
What is Sheet metal gauge thickness?
Sheet Metal gauge represents standard sheet thickness for a specified material. Different material with same gauge number has different sheet thickness.
Gauges are defined based on the material weight and rolling mills. Click this link to check the sheet metal gauge chart.
What is the neutral axis in sheet metal?
When metal is bent the top section is going to undergo compression and the bottom section will be stretched. The line where the transition from compression to stretching occurs is called the neutral axis.
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https://www.smlease.com/entries/sheet-metal-design/sheet-metal-materials/
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Regarding what is the neutral axis in sheet metal ————- When the sheet is subject to bend the top portion(surface) will under go stretched and bottom portion(surface) will be compressed. I have read your article which is mentioned inversely for compression and elongation when the sheet metal is subject to bent.