Skip to main content

Posts

Showing posts with the label Excel for Engineers

Featured Post

Why I Wrote The Sheet Mechanic (And Why Calculations Aren’t Enough)

For engineers who already know the math—but still lose projects. For the last few years, I’ve been sharing technical guides here on Mechanical Design Handbook —how to size a motor, how to calculate fits, and (as you recently read) how to choose between timing belts and ball screws. But after 25 years in industrial automation, I realized something uncomfortable: Projects rarely fail because the math was wrong. They fail because: The client changed the scope three times in one week. A critical vendor lied about a shipping date (and no one verified it). The installation technician couldn’t fit a wrench into the gap we designed. University taught us the physics. It didn’t teach us the reality. That gap is why I wrote my new book, The Sheet Mechanic . This is not a textbook. It is a field manual for the messy, political, and chaotic space between the CAD model and the factory floor. It captures the systems I’ve used to survive industrial projec...
NEW RELEASE: Stop trying to be a Hero. Start being a Mechanic. Get "The Sheet Mechanic" on Amazon »
Disclosure: As an Amazon Associate, I earn from qualifying purchases.

Column Design Guide: A Real-World Example & Excel Tool (Part 6)

Putting Theory into Practice We have covered the theory of Buckling (Part 1) , the Slenderness Ratio (Part 2) , and the critical decision between the Euler and J.B. Johnson formulas (Part 5) . Now, let’s solve a real-world design problem. We will perform the calculation manually first to understand the physics, and then look at how to automate this in Excel. Search for Roark's Formulas for Stress and Strain Advertisement The Design Problem Scenario: A machine designer needs to calculate the allowable load for a rectangular steel column. Material: AISI 1040 Hot-Rolled Steel Dimensions: 80 mm × 30 mm cross-section, 380 mm length. End Conditions: The upper end is pinned; the lower end is welded securely into a socket (Fixed). Figure 1: Our design example: A 380mm long rectangular column with Pinned-Fixed ends. Note that it will buckle along its weakest (30 mm) dimension. Step 1: Geometric Properties First, we ana...

Numerical Differentiation in Excel: Calculating First Derivatives

Numerical methods are powerful tools for mechanical engineering design calculations. In this post, I will demonstrate how to calculate the first derivative (velocity) of a motion profile using numerical methods directly in Microsoft Excel, without the need for specialized math software. While textbooks provide extensive derivations, for practical engineering, we can jump straight to the high-accuracy finite difference formulas. The 5-Point Stencil Formula To calculate the first derivative of a function f(x) with high precision, we use the "Five-Point Stencil" method. This formula utilizes interior points to achieve an error order of h 4 , which is significantly more accurate than standard forward or backward difference methods. f'(x i ) = [ -f(x i+2 ) + 8f(x i+1 ) - 8f(x i-1 ) + f(x i-2 ) ] / 12h Where: i = The current point of interest h = The step size (the distance between points) The smaller the step size ( h ), the higher the a...

Solving Nonlinear Engineering Equations with Excel Goal Seek

Problems in mechanical design often require the solution of nonlinear equations. A classic example is finding the roots of a polynomial stress function: 3x 3 - 20x 2 + 1000x + 12000 = 0 These are known as root solving problems : finding the value of x where f(x) = 0 . While you could solve this by trial and error (guessing values until the result is zero), or use the mathematical Newton-Raphson method , there is a faster way for the practicing engineer. Advertisement In this post, I will share a simple technique to solve these problems instantly on your desktop using Microsoft Excel Goal Seek . No VBA programming or expensive MATLAB license is required. Step-by-Step: Using Goal Seek for Engineering 1. Setup the Spreadsheet Open Excel and set up two cells: one for your input variable ( x ) and one for your equation ( f(x) ). The formula cell must mathematically reference the input cell. 2. Locate the Tool In modern...

DIY Motion Simulation: Visualize Machine Timing with Excel VBA

Motion Simulation with Microsoft Excel Mechanical design usually deals with the movement of several parts. There are a lot of software packages that help simulate the movement of machine parts, such as NX (UG), Solid Edge, and SolidWorks. Advertisement But how do you make a simulation without those expensive software packages? I use Microsoft Excel to simulate my timing diagrams. As you can see in the video above, it provides a clear visual representation of the machine's cycle. How it Works Actually, it is nothing but motion simulation using the graphing method in Microsoft Excel. While it cannot simulate complex 3D collisions or physics like high-end CAD, it helps you get a feel for how your machine will behave according to your timing diagram. This technique uses VBA (Visual Basic for Applications) to control the movements. Here is the general workflow: Prepare the Spreadsheet: Create a table defining the geometry (...