# Fabrication Layout Development of Miter Bend by Geometrical & Numerical Method with Example

In This Post We will learn fabrication Lay-outing of Miter Bend or Fabricated Bend or Segment Bend by Geometrical or Graphical and Numerical Method.

Miter Bend Development is most common in fabrication of pipe line of Big Diameter and also used in various types of ducting fabrication for conveying gases and liquid through it. It has wide application Petrochemical or Liquid or Gas Transporting Industry.

We will discuss in Detail of fabrication layout of Miter bend or Fabricated bend in various aspect also with considering Maximum utilization Metal Plate so that we can minimize our scrap, hence our profitability can be increase by using this approach of the fabrication.

So While Developing layout of Miter Bend we can develop our layout by considering Outside Diameter if we are planning to make pipe of required size first and the Marking layout in pipe and Cutting out profile from this pipe and then fit up the Miter Bend and then welded to it. If we are planning to layout first on flat plat by using mean Dimensions and marking on Plate and rolling by taking marking on outside of the bend and the Cutting of profile and the fit up and welding of it.

## Geometrical or Graphical Method for Layout Development of Miter Bend or Fabricated Bend or Segment Bend:

Steps for Geometrical or Graphical Layout Development of Miter or Fabricated Bend or Segment Bend:

1. Draw elevation and bottom view of segmental bend or Miter Bend.

2. Draw half circle view of the bend as shown in above figure.

3. Divide the circle to equal parts as shown in figure.

4. Project the lines from the divided circle to first part of segmental bend as shown in above figure.

5. Measure and note the distance 1-8,2-9,3-10,4-11,5-12,6-13,7-14 etc

6. Mark all the distance each line as shown in Figure II, III, IV and cut out profile after making and use it for further process of Fabrication.

by using above method we can layout Miter Bend or Fabricated Bend or Segment Bend:

## Numerical Method for Layout Development of Miter Bend or Fabricated Bend or Segment Bend:

Let,

A= miter Angle of Bend or bend angle;

d= Diameter of Bend;

R= Bending Radius or Center to End Dimension.

P= No. of Segment to fabricate

N = No. of Parts to be Divide the base Circle.

So,

Miter Angle A = Angle of Turn / 2*(P-1);

In above case A = 90 / 2*(4-1) = 15 degree;

α = 360 / N;

Hence, Marking length for First & last part will calculate by below formulae;

1-1’=(R+(d/2))*tan(A);

2-2’= (R+(d/2)*cos(α))*tan(A);

3-3’= (R+(d/2)*cos(2α))*tan(A);

4-4’= (R+(d/2)*cos(3α))*tan(A);

5-5’= (R+(d/2)*cos(4α))*tan(A);

6-6’= (R+(d/2)*cos(5α))*tan(A);

7-7’= (R+(d/2)*cos(6α))*tan(A);

And for intermediate Parts Marking length will double of the above value because its included angle will double of the above.

From above Method and above calculated Values We can layout Miter bend easy and simple way this method is useful for learning Basics of layout and know the mathematical and graphical concept behind this development.

And Finally we want share link of our Android Mobile Application for calculating Miter Bend layout by numerical method in faster way. we had made this tool for use of this concept in your mobile for minimize your daily fabrication work.

Miter Bend Layout App: https://play.google.com/store/apps/details?id=com.pinjara_imran5290.Miter_Bend

Example for Miter Bend Layout Using Numerical Method:

Fabricate 90 degree Miter or Segment bend of Diameter 500 mm having bending radius 750 mm and formed in 5 segments.

Miter Angle A = 90/ (2* (5-1)) = 11.25 Degree.

α = 360 / 12 ; α = 30 degree;

1-1’=(R+(d/2))*sin(A); 1-1’= (750+(500/2))*sin(11.25) = 198.9 mm;

2-2’= (R+(d/2)*cos(α))*tan(A); 2-2’= (750+250*cos(30))*tan(11.25) = 192.25 mm;

3-3’= (R+(d/2)*cos(2α))*tan(A); 3-3’= (750+250*cos(60))*tan(11.25) = 174 mm;

4-4’= (R+(d/2)*cos(3α))*tan(A); 4-4’= (750+250*cos(90))*tan(11.25) = 149.2 mm;

5-5’= (R+(d/2)*cos(4α))*tan(A); 5-5’= (750+250*cos(120))*tan(11.25) = 124.3 mm;

6-6’= (R+(d/2)*cos(5α))*tan(A); 6-6’= (750+250*cos(150))*tan(11.25) = 106.1 mm;

7-7’= (R+(d/2)*cos(6α))*tan(A); 7-7’= (750+250*cos(180))*tan(11.25) = 99.4 mm;

By using all the above dimension we can calculate remaining Dimensions for First and last Piece.

For the dimensions of Intermediate part multiply 2 with above calculated Dimensions.

So Dimensions will be,

198.9*2 = 396.4 ;

192.25*2 = 384.5 ;

174*2 = 384 ;

149.2*2 = 298.4;

124.3*2 = 248.6 ;

106.1*2 = 212.2 ;

99.4*2 = 198.8 ;

And arrange the layout as shown in above drawing and cutting out the profile after rolling of pipe & then fit up and welded to make segment Bend.

please share this post and application for those who are in field of fabrication and also give your suggestion making new tools ease of fabrication methods.