Questions tagged [manufacturing-engineering]

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13
votes
3answers
5k views

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
votes
4answers
4k views

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
votes
3answers
426 views

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
votes
2answers
254 views

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
votes
2answers
154 views

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
votes
2answers
711 views

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
votes
1answer
524 views

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 ...
7
votes
1answer
62 views

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
votes
3answers
264 views

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
votes
2answers
85 views

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
votes
3answers
1k views

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
votes
1answer
618 views

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
votes
1answer
150 views

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
votes
2answers
1k views

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
votes
1answer
146 views

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
votes
1answer
774 views

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
votes
1answer
177 views

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
votes
1answer
103 views

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
votes
1answer
117 views

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
votes
1answer
56 views

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
votes
3answers
567 views

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
votes
1answer
419 views

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
votes
2answers
193 views

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 ...
4
votes
1answer
112 views

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
votes
1answer
608 views

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
votes
0answers
29 views

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
votes
3answers
2k views

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
votes
1answer
159 views

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!
3
votes
2answers
13k views

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 ...
3
votes
1answer
65 views

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 ...
3
votes
1answer
53 views

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
votes
1answer
824 views

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
votes
1answer
2k views

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
votes
1answer
71 views

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?
3
votes
2answers
39 views

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, ...
3
votes
3answers
5k views

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 ...
3
votes
1answer
35 views

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 ...
3
votes
2answers
1k views

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
votes
0answers
42 views

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
votes
0answers
45 views

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
votes
2answers
111 views

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
votes
2answers
596 views

What are the design principles for risers in sand casting?

Risers are added reservoirs used to feed liquid metal to solidifying casting. In the case of alloys that shrink during solidification (this is not the case of all alloys), one uses such reservoirs to ...
2
votes
1answer
258 views

What does “bedding-in” mean in casting technology?

I've heard this term used a lot in literature but I don't understand what the technique is they are referring to. Please help me out here.
2
votes
1answer
31 views

Wireless communication modules transmitting through body

I wanted to be able to transmit data from a wireless module to an Arduino. It is possible that a human body could come between the wireless module and the Arduino or someone might cover up the module ...
2
votes
2answers
159 views

Designing bulk material handling system for injection molding

does anyone have any resources for designing a bulk material handling system for an injection molding outfit? Currently we get material in gaylords and vacuum it to the hopper on each molding machine ...
2
votes
3answers
70 views

How to manufacture parts with complex air channels inside?

I am designing a part that requires multiple air channels with an intricate structure inside. I would like to know if there is any state of the art injection molding technique or other technology that ...
2
votes
2answers
163 views

Plastic Injection Moulding a Piece with Undercuts

I am a newcomer to Plastic Injection Molding and would really appreciate some advice. I have a prototype object that will be made from a type of polypropylene. I only need a maximum of 10 units ...
2
votes
1answer
46 views

Can a threaded fastener stretch so much it can be miss-read as a different pitch?

Can a threaded stud of mild steel, size 5/8"-11 over a threaded portion of 1.25" stretch so much over time that it reads 5/8"-13? Unthreaded portion of the stud reads .625-630" in ...
2
votes
1answer
3k views

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://imgur.com/a/7akHC Problem statement: For a sheet ...
2
votes
1answer
35 views

Multicolor dip-painting techniques

I once saw on TV a factory dipping a product into a tank of paint and it magically emerged with a crisp pattern. (It was an Archery bow, and the pattern was army-style camouflage). Was I deceived or ...