question stringlengths 50 10.5k | answer stringlengths 37 15.9k |
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In Autodesk Inventor Professional 2024, I am failing to add a flange to a sheet metal cone (300° for now, eventually the tabs will be used to mount and close the funnel), that is created in a sheet metal part file by
<ol>
<li>Sketching a line and an axis for a Contour Roll (Sheet Metal tab)</li>
<li>Rotating a rectangl... | #### The reason for this seems to be the behavior of the top and bottom faces of the cone, they would make the ends of the flanges weird so that Inventor does not know what to do there. Creating the cone as a 3D model also seems to cause issues with the flange tool. You can solve it by forming the cone via sheet metal ... |
I just can't seem to get it through my head and I don't understand the difference. As far as I can understand, strength is a materials resistance to permanent fracture while stiffness would be resistance to temporary fracture. If possible could I also get a brief explanation of ductility and resistance to fracture, and... | #### <ul>
<li>Stiff and strong: you put a load of one pound on it and it moves 0.000001", you have to put a load of 1000 pounds on it to break it.</li>
<li>Springy* and strong: you put a load of one pound on it and it moves 1", you have to put a load of 1000 pounds on it** to break it.</li>
<li>Springy and we... |
As far as I understand they both relate to the amount of deformation based on a given amount of stress.
| #### Stiff and flexible are opposing qualitative metrics in the elastic regime. Under an applied stress, a stiff material will deform less than a flexible material. When the stress is released, both will return to their origin point (no deformation).
Ductile and brittle are opposing behaviors in the failure regime <em>... |
Strength is just the amount of force that an object can take before breaking, so what is fracture toughness?
| #### Fracture toughness is a measure of the amount of applied work required to initiate a crack in a test sample and then "walk" it all the way across the sample cross-section, so as to tear the sample in two.
In this type of test the load is applied suddenly by smacking the test sample with a heavy hammer ra... |
I live in a 14 story apartment complex built in the 70s that has three underground parking levels.
Today it looks like there's water leaking through cracks in the concrete on the second and third levels of the parking garage in multiple places throughout (not just one concrete block affected).
Is this a I-should-have-l... | #### A pipe or connection to an appliance has cracked and needs to be repaired. Even a defective toilet can leak a lot of water.
Concrete structures can likely take the leak without too much damage. But the source of the leak must be located urgently and fixed. After that, the structure needs to be inspected for any da... |
The maximum reachable efficiency for a heat pump can be calculated using Lorenz/Carnot cycle:
<span class="math-container">$COP = \frac{T_H}{T_H - T_C}$</span>
Where as the <span class="math-container">$T_H$</span> is the target temperature and <span class="math-container">$T_C$</span> is the reservoir temperature (I m... | #### Heat pump efficiency is the heat output over the power input. For heat pumps and refrigeration systems, this efficiency is a positive number because you can move more heat than the energy you put in. So COP is used because calling a system 300% efficient just raises more questions.
Since heat pumps are made to m... |
If we have a mixture of ideal gases can we consider the mixture also an ideal gas?
This holds true in air for example where we consider it an ideal gas, when oxygen and nitrogen are considered ideal.
But does this always hold true?
| #### <h2>A mixture of gases acts like a mix of each individual gas, not like a new entity.</h2>
So yes, it will still act like an ideal gas since it's just the total of all the ideal gases in the mixture. For example, the total pressure of a mixture of gases is equal to the sum of each gas' partial pressure.
Note that... |
What size of drilling screw diameter do I need for
a worn bore thread? (In my case, it is related to eyeglasses.)
The original screw thread diameter is 1.4mm, but since the bore thread is worn,
I need to use a drilling screw that, I assume, should be larger (but not equal) than the original one. If it should be larger ... | #### I am fairly certain that neither self-tapping or self-drilling (not the same thing) screws exist for diameters that small. Furthermore, self-tapping threads that are that fine which are required for lengths that short do not seem workable.
You are also probably not equipped to drill it and tap it even if you had t... |
Suppose I have a room, 10x10x10m with insulated walls (R-value: 4) and a single double-pane window 1x1m (R-value: 0.35).
Now the total thermal power required to keep the room at a desired temperature is given by:
<span class="math-container">$$
P = \left( \frac{6\cdot 10\cdot 10 -1\cdot 1 }{4} + \frac{1\cdot 1}{0.35} \... | #### If this hole is the only opening in the room, there will be a buoyancy-driven exchange flow through it (if the interior is hotter than the exterior, in through the bottom half of the hole and out through the top half of the hole, and vice versa). This exchange flow <a href="http://maeresearch.ucsd.edu/linden/pdf_... |
I am working with FreeCAD 0.20 and Sheet Metal work bench 0.2.63, but universal CAD tips are also welcomed. As shown in the image, I would like to bend sheet metal with smoothly chancing width along the bend. So, I cannot use for example negative extend values causing stair-like features, unless the sharp transitions c... | #### A tip I got elsewhere is to first make the flat sheet with appropriate width transitions, then bend it afterwards. I'll give this approach a try. Other tips are still welcomed, just in case.
|
I am trying to create a device that can measure the rotation of a ring on a finger. Basically there's going to be two rings on the finger, one that rotates and one that is stationary. The idea is that the stationary (or rotating ring, if that's an option) will be able to measure how much it's rotated relative to the st... | #### Have 3 magnets on one, irregularly spaced which will show rotation.
Then Hall effect sensors on the other, as the signals are recorded the relative spacing shows rotation and even direction.
|
I am trying to figure out how to compute torques in a network of rotating objects. I assume that each object has a given moment of inertia, and some objects are accelerated by external means. The objects are connected mechanically by zero-mass rigid connectors. Due to the rigid connections, all objects are forced to ro... | #### This isn't really an answer, sorry in advance.
Not sure the exact language to use, but it seems to me that a cyclic network of rigid connections would be is overconstrained in some sense, and so I don't think we could know how much energy travels in each possible path.
What would be necessary to bring the network ... |
Most optical tables have holes. Are there also optical tables without holes? Or do these things have a different name?
| #### This is called a <a href="https://en.m.wikipedia.org/wiki/Surface_plate" rel="nofollow noreferrer">surface plate</a>.
|
I am trying to build a tool that could help someone/something weld.
<ul>
<li>Being very close to a MIG or TIG welding gun may be dangerous/undesirable.</li>
<li>Welding needs to be done in a straight line (which can be difficult for some people/robots).</li>
<li>Welding needs to be done pretty slowly (which can be diff... | #### Section ABD is same as section GHI.
Extend the BD link to match HIJ.
Constrain C, instead of B.
|
My Inventor model somehow ended up with its coordinate system very misaligned with its faces so that when I try to create a drawing, the orthographic projections I get aren't the best (the top right one is the 'isometric' view):
<a href="https://i.stack.imgur.com/WWLYD.png" rel="nofollow noreferrer"><img src="https://i... | #### I solved my problem : I reset the view cube's "top" and "front" orientations by rotating it to the correct ones, right clicking the cube, and selecting "Set Current view as".
|
I'm doing a static analysis of a square thread lead screw. I think this site gives a good description of the problem.
<a href="https://engineeringstatics.org/Chapter_09-screw-friction.html" rel="nofollow noreferrer">Screw threads statics</a>
To calculate the moment on the thread the mean radius of the thread is used.
... | #### <em>My question is, is the first approach using the mean radius simply a simplification/approximation of the disc friction method of integrating over radius and the later will be more accurate?</em> Yes
<em>Or is it incorrect to integrate over the radius when looking at a screw thread analysis?</em> This would be ... |
Do I need to perform all the lower IPx(1-7) rating tests to achieve an IPx8 rating or covers the IPx8 rating test all the other ones.
| #### The following comes from the <a href="https://assets.new.siemens.com/siemens/assets/api/uuid:7f2844f1-502a-4c23-b123-117894c39a8c/ip-vs-nema-whitepaper-icp-us.pdf" rel="nofollow noreferrer">Siemens summary of the IEC 60529 IP rating</a>:
<blockquote>
Note on the second characteristic numeral (protection
against in... |
In a fully connected truss (each node connected to all other nodes), the number of members (bars) is equal to <span class="math-container">$n(n−1)/2$</span> where <span class="math-container">$n$</span> is the number of nodes.
I don't understand the derivation of this formula. Can you please explain it to me?
reference... | #### There are n nodes. Each connects to all the others, so n-1 connections to each node. But if node A is connected to node B then member AB is the same as BA so you've counted each member twice. Hence /2.
So, (n nodes) x (n-1 connections to each node)/(2 because you have doubled up)
|
What is acceptable connectivity for an Elevator Phone system. As analog systems are going by the way side, Cellular is one option, however is it acceptable to use point to point WIFI bridging to accomplish this task and where in the code regulations is the information regarding this ?
| #### The standard seems to specify 2-way communications, with requirements for testing, alternate power, etc., but does not specify how that should work.
There are a lot of requirements there, but they seem to leave to you how to make it work. The applicable section is 2.27.1 Car Signaling Devices.
|
What do the following annotations mean in this AutoCAD drawing mean?
<pre><code>R1.25 TYP (circle/hole Left)
2XØ1.0 (circle/hole Right)
Ø1.25 (circle/hole Bottom)
</code></pre>
Based on those annotations, what is the diameter (or radius) of each of the three circles/holes in this AutoCAD drawing?
Also, if I'm reading c... | #### The outside circle like you said has a radius of 1.25. The two holes at the top have a radius of 0.5 as you said and the bottom hole has a radius of 0.625.
What the drawing doesn't say I think is the "outside circle" of the bottom and right hole.
|
I have an axisymmetrical part that is subject to an internal (non-constant along the inner border, but constant in time) pressure (among other loads, but this is the one I am interested about) and I have to analytically evaluate the stresses across its cross section.
<a href="https://i.stack.imgur.com/t74Z4.png" rel="n... | #### <h1>Solution using ring</h1>
Using figure from the question:
<a href="https://i.stack.imgur.com/gSgr6.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gSgr6.png" alt="figure from the question" /></a>
<h2>Ring rotation stiffness</h2>
Section <span class="math-container">$\Gamma$</span> rotates by ... |
I am currently designing an axial air compressor for a project, and I require the stator blades to reduce the velocity from 50m/s to 2.5 m/s in each stage of the stator. This requires a ratio of the areas to be 20. Hence, the circumferential gap between the edges of consecutive blades need to have a ratio of 20 through... | #### You are completely missing the point of how an axial compressor operates. Let's say you design it so the axial velocity everywhere in the machine is a constant 2.5 m/s. The area of the flow will reduce in proportion to the density increase. All of the velocity change will occur in the transverse plane as changes t... |
This is a question that has been haunting me my entire career. The pressure loss caused by friction is not the same as the pressure "loss" caused by vacuum, right?
I mean, if I have a gas flowing though a pipe, the more restricted the way is, the bigger is the pressure drop caused by the pipe and therefore it... | #### Consider the fluid as a control volume -- a defined size of the fluid. Pipe friction works at the surface of the control volume to prevent the entire fluid as a unit from moving through the pipe in its desired direction. Pumping (suction as you phrase it) works at the surface of the control volume to move the flui... |
So I understand how H infinity control can be used to synthesize a controller that is in the standard error-feedback framework shown here:
<a href="https://www.researchgate.net/figure/1-DOF-feedback-control-system_fig1_313128407" rel="nofollow noreferrer">https://www.researchgate.net/figure/1-DOF-feedback-control-syste... | #### You can use H-infinity design to optimize any control system that can take the form
<pre><code> ┌─────────┐
z◄───┤ │◄────w
│ P │
y┌───┤ │◄───┐u
│ └─────────┘ │
│ │
│ ┌───┐ │
│ │ │ │
└─────►│ K ├───────┘
│ │
└───┘
</... |
I'm looking for a type of screw like this:
<a href="https://i.stack.imgur.com/Z1FWc.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Z1FWc.png" alt="enter image description here" /></a>
but with even smaller diameter (pin size) smooth end. Preferably M6 thread and less than 2mm diameter end, preferabl... | #### It's called a dog point grub screw and you may be able to find your desired object at <a href="https://www.mcmaster.com/products/grub-screws/" rel="nofollow noreferrer">McMaster-Carr</a>. The site has a selector panel and one of the entries in the panel includes the ability to specify the tip diameter. Notice also... |
I need to design an aluminum enclosure for some electronics, but I have no idea how to screw the different pieces together. I have settled for a folded box design with a top, but I can't figure out how the lid is supposed to be screwed with the rest.
By checking on metal enclosures I have access to, it seems that it is... | #### If the enclosure is going to be opened and closed periodically and you wish to have longer life integrity for this action, consider an alternative method to sheet metal screws.
Self-tapping screws can be found in self-drilling form but that aspect makes the longevity of the fastener even more reduced if repeatedly... |
Consider an almost-rigid part on a vacuum table. There is a flat gasket underneath the part that exposes some portion of the bottom side of the part to vacuum. Let's say 50% of the bottom surface is exposed to the vacuum. Assume the body is flexible enough to seal against the "islands" in the gasket, preventi... | #### It should always be atmospheric pressure x area exposed to the free space of the vacuum.
If MDF is as porous as you say then the MDF itself is acting as a breather material. Incidentally, open-celled foams allow gas to pass through them so if these rubber tiles are made of open-celled foam, these would behave simi... |
I have a compressed gas duster with difluoroethane as the gas. When I shake the bottle, I feel sloshing, so I assume that it is a vapor liquid mixture inside.
When I expel the gas, the can gets cold to the touch.
I thought that liquid vapor mixtures have constant temperature during phase transition. Why does the bottle... | #### I will expand on <a href="https://engineering.stackexchange.com/a/58981/24351">Solar Mike's answer</a>.
The physics/chemistry here is based on the <a href="https://en.wikipedia.org/wiki/Enthalpy_of_vaporization" rel="nofollow noreferrer">Latent heat of Evaporation</a>
As you let you air out of the can, the pressur... |
<strong>Background</strong>
I randomly had this idea and i was wondoring if could it be a better alternate technology than what we use in cars now, but as i have little knowledge in the enginnering field(i'm a physics post graduate student) i had to ask this question here. I had this idea when i was learning transistor... | #### <a href="https://en.wikipedia.org/wiki/Continuously_variable_transmission" rel="nofollow noreferrer">Continuously Variable Transmissions</a> are a thing, and often found in things like snow mobiles and other light vehicles.
They are not as common in heavy vehicles because they don't handle high torque very well, b... |
Is there a way to identify the source of low frequency (166Hz) noise coming from the street (I suspect from the opposite building in the closed yard in the city)?
The noise comes hearable in the yard as well and comes, maybe from the root or vent system, I can’t be quite sure since I don’t have access there and houseke... | #### Several important clues here, as follows.
First we note the very strong 50Hz spike. I will assume from the spelling of your name that you live in a place with 50Hz AC mains. Many different types of electrical machinery running on 50Hz will produce 50HZ noise- in particular, power transformers in which the core lam... |
I have seen the technology for liquid detergent Auto - Dispensing in washing machines where we load the detergent at one go only and the machine automatically dispenses it according to its need for different load cycles.
Now I want a concept and mechanism for the same thing for powdered detergents wherein we load like ... | #### Industrial applications use augers to feed powder.
<a href="https://i.stack.imgur.com/2veNs.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/2veNs.png" alt="enter image description here" /></a>
<em>Figure 1. An auger system. Image source: <a href="https://www.parkerionics.com/powder-coating-equip... |
I came across some of these parts and have no idea what they are. It could be related to bearings, but most likely not. I also have other, similar looking parts but of all different dimensions (with the same shape). Material feels quite hard, almost like ceramic, and is cold to the touch. I am based in the United Kingd... | #### The p/n GC800-70GV2S is listed here:
<a href="https://darmann.com/specifications/product-selection" rel="nofollow noreferrer">darmann.com/specifications/product-selection</a>
Looks like some kind of abrasive shaping or surface finishing tool for production of hip implants
|
I have a few materials that I would like to get cut (in precise shapes that I cant do on a saw), these are
Quartz glass (1mm thick)
alumina wafer (1mm thick) (AL2O3)
copper coated alumina (2mm thick)
I was wondering if it was safe to attempt to cut these in a 150W CO2 laser, or if I am risking damaging myself or the la... | #### If you have a safe enclosure as described by Pete W in a comment, then you reduce the risk to damage yourself or others. Risking the laser is usually avoided by tilting the processing head such that reflected radiation does not return straight into the resonator.
If those worries are taken care of, you can <em>att... |
In structural optimization, we try to design our structure in a way to sustain loads in the best way possible.
An example could be thinking about transmitting loads to fixed supports in an optimal way.
I am thinking of the instant when a load reaches a support. First, before the load reaches the support, it has already... | #### Because the force of the load needs to be counteracted (remember Newton's 3rd law?).
A force doesn't just disappear, it needs to be counteracted or things will start moving (remember Netwon's 2nd law?).
A support is a great way to create a force in the opposite direction that will prevent the force from acting on ... |
I want to cut some 6" diameter holes in 1/8" thick lead sheet that is 12"x12" up to 12" x 24" but would like to minimize dust and debris.
I was thinking that the best approach to minimizing dust and debris would be to use aviation shears to cut out the hole. However, the shears would need ... | #### Use a chisel and hammer. A narrow chisel will allow you to make a hole within the tolerance you need.
|
A general block diagram of a feedback controlled process with a disturbance in the output is:
<a href="https://i.stack.imgur.com/nC1Qk.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nC1Qk.png" alt="enter image description here" /></a>
If we assume that the following blocks are equal to 1, and theref... | #### <blockquote>
For example, if the disturbance is unstable...
Gd = 1/(s-1)
</blockquote>
In that case, the (s-1)^(-1) would be <strong>part of the denominator</strong> after simplification; and hence part of the characteristic equation.
<blockquote>
The literature i've seen always refers only to the characteristic e... |
I have seen this lead/ball screw replacement device in a DIY video, possibly related to 3D printing, but lost the link and could not find how it is properly called.
It consists of a smooth rod clamped tightly by three bearings (ball bearings?) arranged around the rod and fixed to the bed such that rotating the rod (pos... | #### You seem to be referring to this variation of <em>ball screw</em> where a smooth rod is used, instead of a lead screw.
It is (apparently) called a <em><strong>threadless ballscrew</strong></em>.
From <a href="https://hackaday.com/2016/04/28/threadless-ballscrew-for-3d-printer/" rel="nofollow noreferrer">Threadless... |
When we have a T or I section under a shear force <span class="math-container">$V_y$</span> I usually must account for a horizontal shear force across the section's Z axis (<span class="math-container">$_{xz}$</span>). I understand why a transverse shearing force would obviously cause a sliding action downwards. Mathem... | #### If you look at the shear diagram of I section you see shear in the web starts from the top flange at a non-zero value , calaculated by the <span class="math-container">$q=\frac{VQ}{I} \ .$</span> That q on top and bottom are coming from the horizontal tranguluar shear flow in the flanges. The diagram shows how dif... |
I found a 40ft. length of rope for sale at the dollar store. Not having high expectations to start with, I examined the packaging closer out of curiosity. The front of the label states that the rope has 200lbs of tensile strength... Not all that much, but okay, in line with expectations. Turning it over to read the fin... | #### "Rated" means it has been proof-tested by an independent lab (like UL or CSA) according to a published standardized test protocol invented by a standards organization (like ASTM) and sufficient trials have been conducted to achieve statistical significance.
This costs money, and cheap product manufacture... |
Can someone provide the derivation for the following equation:
<span class="math-container">$$\int_l Q_Z(x) dx = M_y (x) \tag1$$</span>
or equivalently :
<span class="math-container">$$\frac{dM_y}{dx}=Q_Z\tag2.$$</span>
I am interested in the <span class="math-container">$1D$</span> isotropic material version.
<a href=... | #### We just integrate and evaluate <span class="math-container">$x$</span> from <span class="math-container">$0$</span> to <span class="math-container">$l$</span>.
<span class="math-container">$$\int_l Q_Z(x) dx = Q_z(x) \ x\biggr\rvert _o^l = Q_z(x)l= M_y(x)$$</span>
|
I am working on a school project where I have to choose a mechanical motion device and create a 3D model of it.
I have chosen <a href="https://507movements.com/mm_090.html" rel="nofollow noreferrer">https://507movements.com/mm_090.html</a> because it seems adequate for my modeling skills. However, I am unable to find a... | #### <a href="https://i.stack.imgur.com/wbGcOm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/wbGcOm.png" alt="enter image description here" /></a>
<em>Figure 1. A Scotch yoke mechanism. The blue part rotates around the small circle. The red part oscillates left and right with simple harmonic-motion... |
I am interested in creating a water dispenser myself for cooling water, and am looking for a cheap and not too engineering complex concept. I found a water dispenser on Aliexpress, for a very cheap price, and am wondering whether you know how the cooling system works?
Link to the water dispenser: <a href="https://de.al... | #### This device only heats. The "cold" water is at room temperature. Check this alternative website:<a href="https://ma2030.com/Home-Appliances/dmwd-550w-household-electric-water-dispenser-desktop-water-heater-mini-water-boiler-drinking-fountain-constant-temperature-95%E2%84%83/" rel="nofollow noreferrer">li... |
There seems to be a lot of information around calculating the forces exerted on a structure. When joining wood, once the structural analysis is done, <strong>how is the performance limit of a certain type of joint determined?</strong>
E.g. building a wooden frame in the garden
<ol>
<li>Building a pergola - Relatively ... | #### <strong>By destructive testing of the different kinds of joints under different kinds and magnitudes of loads</strong>.
This means that joints of various kinds are constructed, then loaded in a particular fashion until they break, taking measurements of the forces needed to deform the joint and/or separate the par... |
How is the fan efficiency zero at the highest flowrate point (at which there is zero pressure rise)? I know the fan efficiency is given as
<span class="math-container">$fan\_efficiency = output\_power/input\_power$</span>
where output_power of the fan is given
<span class="math-container">$Output\_Power = Pressure\_ris... | #### <blockquote>
But even if there is no pressure rise across a fan, the fan does cause the flow to happen by transferring energy (or power) to the fluid.
</blockquote>
Don't assume that the flow in that graph is driven by the fan -- if the fan efficiency is going to zero, that means it is not exerting any net axial f... |
The Schlage FBE365 electronic deadbolt uses a DC motor attached to a helical screw to raise and lower the C-shaped piece shown. The way the rest of the mechanism works is not important for this question - all that matters is that the C-shaped piece needs to go up and then down and it does that by rotating a motor and ... | #### The reason drive screws are used is because they give mechanical advantage.
Solenoids are linear devices and don't have inherent use leverage for mechanical advantage. A rotary motor with a small lever arm produces more force and somewhat decouples the actuator length from the motor size. A solenoid gets only one ... |
If I have a 40A 3 pole Miniature Circuit Breaker ("mcb"), does this mean 40a per pole or 40A altogether?
The quality standards made me write some more so I do it.
| #### 40 A per pole.
That's the way three-phase loads are specified so that's the way the breakers are specified.
It also means that a single phase exceeding the trip current (due, for example, to a partial earth fault on that phase) will trip the whole circuit.
|
I am still pretty new to control theory, but I have been studying both classical and modern state space/optimal control ideas. I am having trouble understanding what the frequency domain/transfer function view is on some of the challenges of optimal control, for example the inverted pendulum swing-up problem.
<em>Probl... | #### <blockquote>
how to formulate this same problems as a <strong>transfer function</strong> or in the <strong>frequency domain</strong>? I mean I could compute the transfer function for the pendulum equation.
</blockquote>
The range of motion involved in bringing a pendulum from <em>down</em> position to <em>up</em> ... |
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