Questions tagged [manufacturing-engineering]
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230
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Measuring longer distances with high accuracy
I am involved right now in the fabrication of steel structures on the order of 5-50 feet long. Presently, we measure these structures with garden variety commercial tape measures. Most of the time, we ...
11
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4
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Why are most jigsaw blades designed to cut on the up stroke and have teeth that point towards the shank?
Why are most jigsaw blades designed to cut on the up stroke with teeth that point towards the shank? Why are reverse teeth jigsaw blades less popular?
11
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3
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485
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Why are mass-produced metal parts machined by rotating the part against a stationary tool?
There's a TV programme called "How It's Made" which often shows automation of mass-produced machined parts. Very often, it seems that metal parts are machined (especially drilled) by rotating the part ...
10
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2
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What's this mystery symbol on a manufactured machine?
I hope this is the right place to ask this question; if not I'd really appreciate some tips as to where else I can go for answers.
The symbol above (apologies for the blurry quality) is on a Chinese/...
9
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6
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How to work on big CAD project in team?
I'm always confused on what is the effective way to work on CAD with multiple team members to make it efficient. So far, as I'm freshly graduated I only work on a project where I'm the only one using ...
9
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2
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204
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Material selection for weight scale
I am looking to test the FlexiForce sensor in measure force, however for accurate readings the load needs to be disturbed evenly over the sensing area. As such I am having "discs" made to cover the ...
7
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2
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720
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Line balancing - How far do companies go? [closed]
I understand that the concept of line balancing is such that each station takes exactly the same amount of time to process one unit. Clearly, this is an idealization and real manufacturing plants will ...
7
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1
answer
84
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What is a method to detect thermal oxide layer after steel is painted?
Is there a method to test for thermal oxide on a painted steel part after the paint has cured? I'd rather the method be nondestructive but it only being destructive in the presence of thermal oxide ...
6
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3
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285
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How can the vendor be approved/disapproved based on validation test data?
The power requirement for a sub system is 5V +/- 10% @ 1A of current. A RFQ was issued and a prospect vendor was selected. A first article of inspection (FAIR) has been submitted which includes 15 ...
6
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2
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114
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Does every engineering design needs to have a complete theoretical backing or may experimental data suffice?
This may sound rather vague on its own so I will explain with examples.
The solid booster rockets used by NASA space shuttle used a central bore design because it had a certain characteristic on ...
6
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How to manufacture cutting dies for metal foil?
I am making a die for cutting arbitrary shapes from thin (0.1–0.5 mm) copper foil/sheet using a manual arbour press. The product will be an oak leaf shape, approximately life-size, for use as part of ...
6
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1
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667
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How do the dimensions of a ductile iron casting change as it cools?
I am designing a pattern for a sand casting. It has only one critical dimension which is a 4" inner diameter cylinder. If I use a 4" core, will the casting shrink away from the core? In other words ...
5
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1
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197
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Limits of Injection Molding Regarding Overhung Edges
I'm looking to redesign a seal my company currently uses. The original task was to re-source it from a lower cost supplier with the same design as is in current production. However, the supplier doesn'...
5
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1
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How are non-continuous internal threads plastic injection molded?
I'm trying to figure out how the heck some of these plastic bottle caps are injection molded. By having the thread on the inside of a cap, this obviously creates an undercut.
Now I've watched some ...
5
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2
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What are 'inside' and 'outside' dimensions in reference to castings?
I am looking at a company-written standard for cast parts. The castings are blanks for driveshaft yokes, similar to what is pictured below. The standard defines general tolerances for the dimensions ...
4
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2
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How do I manufacture a fillet?
What are the most popular and the most efficient ways to machine a fillet on an external edge of an object? If I were to use a CNC mill, what tools can I use for it, and how would the method change ...
4
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1
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254
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Purpose and name of fine pitch marks on a cast metal part
I have seen this kind of mark on various cast metal parts. This is an image of the base casting of a hard disk drive made by HGST.
What are these marks for?
What are they called?
4
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1
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How do I cut a crack into a polymer/plastic?
We need to cut a very thin crack into a polymer plate for a research project. The closest thing to what we are looking for is Wire EDM but since the polymer we are using is not conductive we cant use ...
4
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1
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246
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Is it feasible to forge multiple, smaller parts in the same forging operation?
Let us assume you have a large forging press or drophammer, and drawings for a set of smaller parts that all need to be forged from the same material. Would it be feasible to construct a forging die ...
4
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1
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627
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Real world applications where one would use a force function in PLC programming?
I'm curious about which scenarios one would use a force function when using a PLC programming interface. Examples pertaining to process engineering, manufacturing, or industrial settings would be ...
4
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1
answer
63
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Can graphene really be made in a modest lab at home?
I have seen some resources on the Internet that claim to be able to make sheets of graphene (single atom thick lattice of hex-bonding carbon) from commercial off the shelf materials and a modest lab ...
4
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1
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138
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Why can't red flint glass be produced?
I recently went on a tour of a glass manufacturing facility who produce bottles for the prestige alcohol market. I was informed on the tour that red glass cannot be directly produced - any bottles ...
4
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2
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708
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Why do monocrystalline solar cells have rounded/cropped edges?
What is the meaning of this croped part? Why do they crop it, rather than let it be full square?
4
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1
answer
196
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What is the name of optimizing space between laser cut parts?
When we send some drawings to laser cut operation, they use a proprietary software (usually specific to the laser machine) to duplicate the drawings per request, with the spaces between parts ...
4
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3
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624
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How to select the correct grinding wheel type for precision grinding of tool steels?
I am planning to move from conventional grinding wheels to super-abrasive grinding wheels. I am unable to decide the right type of super-abrasive wheel for my manufacturing operations (I am into knife ...
4
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1
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554
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What is the accuracy of direct metal laser sintering (DMLS)?
They've printed jet engines with it that work after polishing. So how is the accuracy measured and how accurate is the DMLS process? I can't find the required info anywhere.
4
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1
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459
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How is linear motion achieved in this automatic blackboard eraser?
In the animation shown below what can be the mechanism used for this purpose? I know it can be achieved by using rack and pnion gear arrangement. But how are this set up arranged in classroom ...
4
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2
answers
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How to estimate the time cost of interrupting a task and picking it up again later
In terms of personal productivity (single machine scheduling) when a task is interrupted before being done in order to switch to a different task, it incurres a 'tear down' time cost - putting tools, ...
4
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3
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How were gears manufactured before power tools, CNC, etc
Current gear manufacturing methods for gears usually depend on power tools, or computerised machines, or something like that.
However, watchmakers and clockmakers at one point in history needed to ...
4
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1
answer
48
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Cleaning tape for automatic part cleaning during manufacturing
Is there something like a consumable cleaning tape for automatically cleaning parts during manufacturing? Some parts need to be cleaned before automatic assembly, e.g. magnets before adhesive being ...
4
votes
1
answer
892
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What actually cause quench cracking, non-uniform cooling or rapid cooling?
It’s well known that quenching most alloyed steels starting from AISI 4140 to high speed steels in water, brine , or sometimes oil will cause cracking and distortions.
In industry, oil quenching is ...
4
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1
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765
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Bend allowances when making a C-shape plate
I am trying to find the formulas for making bends in sheet metal. I understand there are formulas for bend allowances. My issue is how do I determine where to bend if I want the inside dimension to be ...
4
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0
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Pretreatment for galvanizing primer
I currently need to paint a steel structure with galvanizing primer. The primer is an epoxy with >90% Zinc content. The TDS for the primer states that intimate contact with the substrate is needed ...
3
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3
answers
3k
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Work hardening?
Can some please explain why is the elastic modulus of aluminium and
work hardened aluminium the same?
Is it only the same for pure metals?
3
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2
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1k
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Definition of the "specific material removal rate"?
I've run across a term in some grinding manufacturing research papers called the specific material removal rate. The units given for this term are [mm$^3$/mm$\cdot$s] (I don't really like this style ...
3
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1
answer
116
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Is there a reason why both plasticizer and vulcanizing agent are needed during processing of rubber?
According to this Wikipedia page, vulcanization is an important process to make rubber harder and more durable. However, another Wikipedia page says that plasticizers play a significant role in rubber ...
3
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1
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Sheet Metal Bending: stuck on calculating the minimum radius required
I'm used to calculate the minimum radius required for bending operations on both aluminum and steel sheets, given the following parameters: https://i.stack.imgur.com/yxEBc.jpg
Problem statement:
...
3
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2
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198
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Understanding redundant pharmaceutical packaging
I ran across an interesting combination of packaging for some medicine the other day.
The medicine in question was a prescription migraine medication. The exterior, cardboard package that it came in ...
3
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1
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2k
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How to design electronics to mitigate tin whiskers?
Tin Whiskers are a major problem in the design of electronic circuits and the manufacturing of electronic hardware.
What are Tin Whiskers? How can electronic products be design to mitigate the issue ...
3
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2
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Is the Stop-Start technology detrimental or good for the car?
I found a lot of articles on internet about how bad the stop-start technology is for your car and how it contributes to the faster wear of multiple parts, or how superb the feature is for the Sacred ...
3
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3
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Shade tree engineer needs help calculating hoop stress
I have an extruded aluminum tube. I'm trying to come up with an Excel calculator that will help me find out how much force would be exerted on the internal walls if the tube was filled with rubber, ...
3
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1
answer
495
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press fit ball joint
I enjoy creating mechanical designs but I am not a trained mechanical engineer.
I have a technical issue with a joint design that needs to be permanently retained using a press (snap) fit. Any idea ...
3
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2
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2k
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How to attach lycra / leather to Polyurethane foam?
What would be the best solution for attaching polyurethane foam to a lycra sheet of material. I was thinking a chain or pad stitch or possibly glue, but not sure if sewing would be the best ...
3
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0
answers
67
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Plastic hardness after machining vs molding
Should there be any difference in the hardness of a plastic material that is machined vs one that is pressed from a mold?
This question is in specific reference to vinyl record production where ...
3
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0
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148
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Aerospace bolts and washer combination
In my aerospace company we have repetitive discussions regarding the stacking of low tolerance fasteners with non-countersunk washers. For example a fastner NAS6703-X (size 10) has a max. base radius ...
3
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0
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73
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What kind of professional(s) build/design factories? [closed]
I have a small self-built food processing unit (500sqft) but it is very labor-intensive. I want to make a larger unit (45,000sqft) with 100x more output using factory machinery (automation, conveyor ...
3
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2
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What is the percentage of direct workers in an automotive production plant compared to all the employees?
I am not asking for specific numbers of any production plant. I want to know the general direct worker/employee ratio of a plant.
Example: if there are 1000 employees working usually 700 of them are ...
2
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1
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171
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What is the name for a removable sewn bag stitch?
This stitch is composed of a single string/thread and is common on dogfood and grain sacks. It can be removed by just pulling on the end. Here is an example I found on youtube.
Thanks!
2
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1
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Why laser cutting speed suddenly decrease when cutting sheets from 1 to 3mm thickness then stabilize?
Please to understand what I mean, see the picture below :
I don't understand why it is not a linear curve (or almost), because at first sight it should be no ?
If you need 10 sec to cut a length of ...
2
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3
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Small scale manufacturing [closed]
Some background: I am working for an ed-tech startup and we are hoping to release our first product soon but have been hitting a lot of hurdles with our current manufacturing strategy. We want to ...