ME1071: Manufacturing Technology
Semester: 2
Familiarisation with Sheet-Metal Forming
By
Index No. Name Marks
220695E Wickramage YN
Date of commencement 25/03/2024
Date of submission 08/04/2024
Instructors’ name and affiliation
Mr
Department of Mechanical Engineering, University of Moratuwa
I.K.Kariyawasam
Department of Mechanical Engineering
University of Moratuwa
Sri Lanka
Table of Contents
Table of Contents ................................................................................................................... 1
1 Introduction ........................................................................................................................ 2
2 Part 1 .................................................................................................................................. 3
3 Part 2 .................................................................................................................................. 5
4 Part 3 .................................................................................................................................. 6
5 Conclusions ........................................................................................................................ 8
6 Worksheets ......................................................................................................................... 9
7 References ........................................................................................................................ 11
1
1 Introduction
Sheet metal work is fundamental skill in many industries including manufacturing,
construction, automotive, and aerospace. It involves the fabrication of thin, flat pieces of metal
into various shapes and structures.
Sheet metal varies on their thickness. In most of the part of the world thicknesses measured by
mm but in US measurement called gauge is used[1]. Sheet metals which are less than 0.2mm
called foil and sheet metals between 0.5mm and 6 mm called are the ones we normally called
as normal sheet metals. Beyond 6mm lies metal plates. Various types of metals and alloys used
to create sheet metal, like aluminium, copper, iron, brass etc.
2
2 Part 1
Materials and Apparatus.
• Steel Ruler.
• Scriber
• Spot welding machine.
• Tinmen’s mallet
• Folding machine
• Brick iron machine
• Metal sheet
• Divider
• Blow horn stake.
• Brick iron stake.
Procedure
• 2 diagonal lines were drawn in the square shaped sheet metal, scriber and steel
ruler were used.
• The centre was marked by pressing the scriber slightly onto the metal sheet.
• Then circle of 50mm radius was drawn using the divider.
• Then hexagon was marked inside the with the divider without changing the
50mm distance. Using the scriber hexagon was drawn by connecting the
marked points.
• Using the steel ruler, with aligning 2 opposite corners of the hexagon 12 lines
were drawn to draw 6 rectangles on the hexagon.
• to complete the rectangles, at 22mm spot was marked from corner of the rectangle
then the distance between that point and centre of the circle was marked with the
divider and circle was drawn with that length as the radius.
• then the intersection of the straight lines and the circle was marked and using
those points 6 rectangles were drawn.
3
• using the divider lines were drawn by 4mm away from the rectangle top and
right edges.
• Then 45-degree angles were drawn in corners using divider and steel ruler.
• using metal shears drawn shape was cutout.
• Then the metal piece was flatten using the tinman’s mallet.
• 4mm edges were folded inward by 180 degrees using the folding machine.
• Using hand rectangular faces was bended by 90 degrees inwards, then 4mm
edges in right corners of the rectangles was bended using wooden mallet.
• Finally open ends of the box were welded using spot welding machine.
• Finally, box was smoothen using the wooden mallet.
4
3 Part 2
Safety precautions followed in sheet metal shop.
• Wear safety googles and glasses while welding.
• be careful when using equipment like slip rolls, notching machines, bar folder
machines, and hand tools like snips, hand notches, mallets, or hammers as they can
injure your hands and fingers.
• Wear gloves when working with the sharp equipment.
• Always use the suitable equipment for work.
• Use the right lifting technique.
• Cleanup after handling.
Bending Process [2]
The process of shaping metal into various geometries by applying force to cause
plastic deformation (exceeding the yield strength) is known as sheet metal bending.
Ther are several machines and dies to perform the bending and wooden mallet is used
with dies to perform the bending by hand.
Importance of considering the spring back effect
The spring-back effect refers to the alteration in shape that occurs when pressure used for
bending a sheet is released. This change happens because the elastic energy retained in the bent
section seeks to revert to its original form. Consequently, deep-drawn, and stretch-drawn
components spring back, causing variations in the dimensions of the bent sheet. Notably,
bending techniques like bottoming and coining exhibit relatively low spring-back effects.
Challenges stemming from spring-back include deviations from the intended final shape post-
bending and inapplicability of tools due to dimensional disparities. Hence, acknowledging the
spring-back effect is crucial. Presently, software compensates for spring-back, enabling
adjustment of parts to meet specified dimensions and mitigate the mentioned issues.
5
4 Part 3
Designing of a pattern to produce a development for a rectangular duct with end
connections.
Tools and materials
• Steel ruler
• Tinmen’s hammer
• Folding machine
• Scriber
• Metal sheet
• Straight hand shear
• Spot welding machine.
Procedure
• Draw the sketches on a metal sheet with scriber and a steel ruler.
• Then cut the shape with metal shears and the lines marked by X.
• then the edges were folded by folding machine.
6
• Metal shape from fig A was weld like the sketch below.
• Then 1 piece from fig B and 4 pieces from fig C were welded together like
fig.E.
• Then do that once again to complete the other end of the duct.
• Then the final structure should look like this.
7
5 Conclusions
Importance of sheet metal and their usage on the industry was very large. From choosing the
desired metal for the application, cutting, bending, and assembly, each role plays important
task on achieving desired product.
And the importance of proper techniques and tools used in sheet metal industry, such as using
wooden mallet instead of metal ones to ensure the safety of the sheet metal .
While working on sheet metals, safety is very important because of the bending and cutting
involved with sheet metal operations, so following proper methods and techniques is very
important, and following special methods such as cutting small notches in the edges before
folding to avoid overlapping at the corners is also crucial in making a product.
8
6 Worksheets
9
10
7 References
[1]"Sheet Metal - Materials, Standard Sizes ", Fractory, 27 Jan. 2021. Available:
https://fractory.com/sheet-metal/.
[2]"sheet metal bending", Xometry, 8 Sep. 2023. Available:
https://xometry.com/resources/sheet/sheet-metal-bending/#:~:text=Sheet metal bending is the,
electronic casings, and brackets.
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