# Questions tagged [machine-design]

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21 views

### gear compatibility specification

I want to build a epicyclic gear system with planetary gears on flat carrier plate and outer ring as internally toothed (geared) slewing bearing. I want to buy a single row slewing bearing of 8 inch ...
2k views

### Aluminum weight saving

"Aluminum saves weight! Its 3 times lighter than steel!" Also its 3 times weaker and 3 times softer. When comparing stiffness and strenght to weight ratio, aluminum isnt any better than ...
25 views

### Reaction forces on a three support continuous beam with two of them requiring compatibility equations. Superposition method done wrong!

I need to analyze a continuous beam of length L and three supports: A (at x=0), B (at x=L/2), and C (at x=L). An applied load P is applied at x=3L/4. Now, at A, the continuous beam is bolted to a ...
42 views

### Can tubes for fits & tolerance be purchased or only manufactured?

I'm currently designing a steel structure for a gym machine. I want to assemble two rectangular tubes, one being able to slide inside the other, for height adjusting. I intend to use a spring ball pop ...
24 views

### Reference design for a HSK machine spindle?

Is there a reference design somewhere on the web for a HSK milling machine spindle (mainly HSK type A, between 40-63)? I'm mainly looking at the fixating mechanism (drawbar et al) and its tolerances; ...
18 views

### Sign convention for angular velocities in 3D gear train

Consider a Humpage gear train shown above. We are viewing the gear train from right and gear B is rotating in clockwise direction. If we consider clockwise direction as positive what will be the sign ...
87 views

### Velocity or Speed Ratios in Gears and Gear Trains

I have seen the different definitions of the velocity ratio for Gears and Gear trains. I have referred a book called Theory of machines by S. S. Ratan. In that book the definitions are as following: ...
44 views

### In an open belt drive, which angle of wrap should be taken for calculating tension in the belt?

An open belt drive with flat belt has different angle of wrap on the larger and smaller pulley. I have to calculate a tension in the pulley. We generally use the formulae Here θ is the angle of wrap. ...
4k views

### How do vending machines prevent people from stealing goods?

I never understood mechanically how a vending machine prevents people from accessing goods through the dispensing panel. From what I understand it's not a locked door that unlocks only upon payment, ...
39 views

### Can a semi-conductor cooler be powerful enough for a room? [duplicate]

I see semiconductors used for small fridges. I cannot find one large enough to cool a room (in place of a conventional Freon based, window air-conditioner). What engineering problems might a up scaled ...
31 views

### How is the assumption that stress and strain are elastic everywhere is valid for STRESS-LIFE method for fatigue life calculation?

Stress life method is generally employed for high-cycle fatigue (HCF) applications. while HCF region is approximated by $\sigma=a(N)^b$ which gives a linear graph on log-log scale, for steels it ...
64 views

### What type of electrical machine component for counting time?

I am looking for the proper piece of hardware to do what I'm looking for on my current prototype machine build. I want a timer to begin counting upwards in seconds when a switch is activated, and ...
26 views

### How to determine minimum aluminum t-slot profile type for frame?

For a frame with dimensions 1000x1000x400, I am determining which T-slot extrusion type will be strong enough. I am considering both 30-6060 (30 series I-type, metric) and 20-4040 (20 series I-type, ...
52 views

### Is it possible to narrow down a portion of shaft to its 1/5 of its diameter?

I designed this shaft for my center gripper. However the slot requires to be very deep, as you can see. I want to know if it's possible to produce this part. The main diameter is 30 mm and the small ...
60 views

### How do I read this schematic drawing notation for a drill hole?

It's for an NX part. I can't figure out the depths and such. I just know the placement of the 4 holes and that the diameters are 10 mm each.
46 views

### Number of Kinematic Pairs

Kinematic pairs are the connection between 2 links that can have relative motion between them. But In six bar chain as shown below: There are five pairs for them to be a kinematic chain. But if I ...
52 views

### Machine Analysis Problem: Finding the vertical force at joint K

Help me in determining the right solution in this problem. I already have an initial solution here but when I compute, my answer does not match to the answer key. I would like to know where did I ...
57 views

### How to measure a dovetail slot and it's mating component?

I have had some trouble determining the best way to measure a dovetail slot and it's mating component. The parts have some difficulty mating occasionally, and our QC department is having trouble ...
43 views

### static friction of gear pair

Im working on a project that has gearing system integrated. From my simulation results im dealing with a relatively small amount of input force at the gearbox and would like to know if the force would ...
54 views

### Sleeve and cotter joint

What does 0.1D signify in this cotter joint. I meant is it denotes spacing between pin and hole. I am new to machine drawing , kindly let me know. Thanks in advance
131 views

### Relation between links and pairs in Kinematic chain

I came across a equation for kinematic chain (for lower pairs only) : L = 2P-4 where L: Number of Links; P is the number of pairs how could this equation be derived ? EDIT: I tried putting values in ...
47 views

### 3D linkage design - terminology

I am designing an animatronic head, which has five degrees of freedom: pitch, roll and yaw for the head part, and pitch and yaw for the neck part. However, the yaw movements for the head and neck are ...
23 views

### How to find a reference line for " Form Tolerances"?

In my project I have to choose a form tolerances ( parallelism ) between the handle ( purple part ) and the part that sits inside it ( the grey part ), where the two parts slide on each other. But I ...
71 views

### Mechanical Engineering: How To Amplify Kinetic Energy In Axial Rotational Gear Machinery? [closed]

When I originally posted this question 2021-04-08, I was inspired by pulley physics, especially after viewing these videos at this link and this link and this link. It is not necessary to go to these ...
45 views

### Gear configuration for a legged hexapod

I have an assignment for my Mobile Robotics course to design the drive mechanism for a legged hexapod and demonstrate its gait in motion. The idea is to design the hexapod as per the following ...
30 views

### Shape of the shaft of knurling device

I'm trying to design and simulate a simple knurling device. The shaft ( blue part ) has a flat surface at the other end, where the small grey pin connect the green body to the shaft. I guess you can ...
49 views

### Applying ISO fits to radial bearings

Do you need to take the bearing size tolerance into account when creating the tolerances for the mating hole/shaft when using ISO 286 tolerances? For example, a 125 mm OD bearing with a desired H7 ...
50 views

### Design a Jig and Fixture for 3-axis CNC Milling Machine

Newbie Here!!! This is my assignment task. I am required to design a Jig and Fixture for 3-axis CNC Milling Machine. The workpiece will be a simple aluminium block and it will be cut and shaped into a ...
44 views

### What is the name for a low pressure, low volume air reservoir?

I'm working on a project that requires very precise, but low pressure controls. I'm using a pump to charge a chamber to <15kPa, then a manifold of proportional valves to control output pressures ...
37 views

### how do i keep static deflection in a spring at a minimum upon applying gravity in a mass spring system without altering the response?

i modelled a simple mass spring damper system (with a vertical orientation) with base excitation in solidworks. After applying all necessary parameters, i plotted responses with and without gravity ...
84 views

### Where water goes in split air conditioner system in "dry" mode?

In split air conditioners, there are two tubes connecting the indoor unit and the outdoor unit. According to the generic schematics I find online (like this one), they are part of the closed circuit ...
204 views

### How can I decrease strip tension with bridle rolls in tension leveller? How can I find total elongation after the strip exits initial bridle rolls?

I'm working on a tension leveller design which consists of 3 main sections. These are Input Bridle Rolls Zone: Increase the strip tension coming out of the decoiler. Leveller Zone: Strip goes through ...
30 views

### How to disassemble this eccentric bushing

This eccentric bushing: belongs to the hand crank of this machine: It cannot be seen clearly in the photo, but the small blocking bar inside the bushing is not hovering over but rather, is sunk into ...
51 views

### What is this strange nut and what to do with it

I bought a cheap version of this machine, because all decent ones had costs of hundreds of dollars of transport to my region. The machine seems to be made of solid parts, but is really badly assembled....
299 views

### Why one big cargo ship is more efficient than 10 or 100 smaller ships?

Given the fact that small container ships are easier to manufacture than big container ships.. then why is it considered better to build bigger ships instead of many smaller ships? And to see why ...
68 views

### Looking for dropping servo mechanism idea

My friend and I have an idea to make prototype of vending machine. We need suggestions for making strong dropping mechanism. The idea is: The user orders X item. Let's take a can of cola for example. ...
39 views

### Safety types and definition [closed]

I am searching for some Engineering terms but couldn't find any of the definition. Direct safety Indirect safety Warnings Thank you in advance
51 views

### What would be the best mechanism to rotate a plate from 0 to 15 degrees?

I'm designing a machine in a small university project that change position of a two-state gate. The two states shown in the Figure below are 0 and 17 degrees of elevation, correspondingly. The ...
58 views

### What does it mean for a machine design to be "kinematic"?

I've seen the term "kinematic" used qualitatively to describe machines several times in books and on YouTube. I think I understand what kinematics is as a study, but I'm not sure what people ...
62 views

### Is there any way to conserve energy for the following scenario of lifting weight?

A pulley can be used to provide mechanical advantage while lifting weight. Suppose a combination pulley is made such that in order to lift something four times heavier, one can use the same force but ...
348 views

### What is "reversal" in mechanical engineering drawing?

I've come across these terms "reversals allowed" and "reversals not allowed" in a sample drawing while reading a GD&T course. What exactly are these terms? What do they mean?
71 views

### Adding the effects of two rods to move a single rod

I have to deal with a situation where I have two parallel and completely independent rods whose motion is dependent only on external inputs, and I want to add up the lengths traveled by each rod. My ...
67 views

### Bending moment when there are no constraints

I faced this problem in an old book (Hall Allen S., Theory and Problems of Machine Design; 1961) The answer according to the book is 592 [in.lb], but I think the bending moment should be 0 because ...
46 views

### A device to provide real-time proportional resistance to variable force

I'm considering a potential product but I'm not sure about the core technology I'd need. The fundamental idea is that there would be a cable (or something similar) that would be pulled. But as it ...
54 views

### Mechanical design of a bioreactor

What books and online materials exist that explain the mechanical design of a bioreactor? Can someone recommend any?
47 views

### Differentiating between Two Orthographic Projections

I came across the infamous control handle assembly in two different books, referencing the views differently. One of the had it like the following photo The other book labelled the side view in this ...
39 views

I'm doing my first machine design for a project and I have a Honda GX160 combustion motor which has the following specs for power and speed: I'd like to use 0.24 HP at 2000 rpm. Is this possible? Or ...
1k views

### Toggle position of a fourbar slider-crank

In the fourbar mechanism as in the following picture, I have to find the toggle position, the sliding distance and the time ratio. Here is my understanding/plan to do this: The toggle positions ("...