24

The photo you have is not for the standard jigsaw blade. Standard blades teeth point upward and cut upward for the obvious reasons: less wobble, more control, center of force near the handle. This is a revers cut blade designed to cut on downstroke to cut laminated work like countertops, so that the cut is not going to splinter the Formica or other laminate ...


16

If you think what happens as each tooth cuts material then the blade is put into tension as it cuts, this means that the blade is likely to stay straight, but any unevenness between the teeth side to side may cause drift. If the blade cuts on the downstroke it will buckle as it is relatively thin for its length. A blade designed to cut on the downstroke ...


11

To enlarge slightly upon Solar Mike's response, a jigsaw that cuts on the upstroke tends to yank the saw shoe down into firm contact with the workpiece. This guarantees that the cut angle will match the shoe angle; for a shoe angle of 90 degrees this means a nice square cut.


9

TL;DR: It depends, but probably not You might argue that "all 15 samples are within spec, so the supplier should be approved". Not so fast: depending on the parameters of your full production run, the 15 samples may or may not be statistically significant. There are numerous calculators online to do these calculations; I used this one. A good resource for ...


9

I can answer for the Chemicals Sector I'm familiar with: Overall line balancing is quite poor between processing operations. 10% difference would be surprisingly good. 50% difference isn't uncommon. Several reasons for this I can think of: Lot of equipment comes in discrete sizes. e.g. Compressors, Centrifuges etc So often the next size higher means you ...


8

Which of the following materials will be most suitable to manufacture the disc for the stiffest/strongest possible part. It seems that you need a material that will transform a non-uniform load into a more-or-less uniform load by providing consistent bearing. As such, you're looking at something like a plate on an elastic foundation, albeit on a much ...


8

You can be sure the resulting surface is round. If you used a router and rotated the bit around the piece then you would get inaccuracies due to the movement being harder to control. Using a lathe-like setup the cutting tool is just a chisel that is cheaper to replace and refurbish when it's worn down than a router bit.


7

Ductile iron is actually likely to expand during the casting process, as shown in the table found on the Casting Wikipeda page, which is in part cited from this casting text by Stefanescu. However, as the tables show, the range of volume change is fairly large and not one-sided, which is to say the ductile iron may either expand or contract depending on ...


7

Are any designs based solely on data from trial and error used in critical mainstream engineering? Usually not. And the reason is that trial and error is expensive and time consuming. As engineers, we are always working on projects with a budget and a deadline. Take your rocket example. Rockets are expensive. For sake of argument, let's just say it's $1 ...


6

To get that sort of accuracy over that scale is not trivial and probably won't be cheap. For smaller size up to a few meters a portable CMM would be an option (here's an example). These have accuracy on the order of 10 $\mu$m and are used for things like high end/F1 car manufacture. However, CMM type instruments wouldn't be useful for anything larger than ...


6

these are part-tracking marks. they indicate which cavity in the mold the part was cast from, in which mold set, in what molding machine, in what year, month, day and shift. this way, a part that fails its finished goods inspection or failed in the field can be tracked backwards through the factory to its source, and the reason for the failure fixed.


6

It is called "chain stitch" and was the stitch used in the first designs of sewing machines, because it is easy to produce mechanically. The fact that it can be pulled out unless the end of the string is knotted (as explained in the OP's video link) is a disadvantage for most purposes. For example, if the string breaks one side of the break will often ...


5

Since you used some specific words in your question, I will respond a certain way. Cracks are generated by mechanical action, and cannot be machined in. They may, in certain brittle materials, be a byproduct of machining. Using a method like EDM will alter the properties of a polymer nearby, as it will heat the polymer. If you are interested in ...


5

I've previously worked in the forging industry and you can certainly forge multiple parts in a single stroke of a large press but there are problems. The obvious ones are the size of the available press and the economics of the operation. However, even from a metallurgical point of view, forging a complex part like a crankshaft in one stroke would induce ...


5

Even the best metal tape measure is susceptible to significant thermal expansion over large distances. Try a laser measurement device ('electronic tape measure') instead: http://www.engineersupply.com/Laser-Measurers.aspx The laser distance measure, flat plates clamped to the object, and some shims of known thickness, should be all you need to precisely ...


5

Work hardening is done to increase the strength of the material, not the stiffness. You change the yield stress to be closer to the failure stress of the material. If I understand it correctly it also increases the elastic range and takes away from the plastic range of deformation (which seems reasonable as it requires plastic deformation to work harden in ...


5

My best guess after a couple minutes of Googling is that this is a CMC certification which stands for China Metrology Certification. If you search for that however, the first result points to China Metrology Accreditation which has a logo nearly identical to that one. That first result is at this link. The logo you will find looks like this: I have no ...


5

This happens all the time in the minerals industry where people need to blend material from different stockpiles to produce a supposedly uniform product for a processing plant. Depending on the size of each stockpile either a front end loader or a bucket wheel excavator are used to take some material from one pile and deposit it elsewhere. You can get fancy ...


5

To expand on Solar Mike's answer and to help explain part of niels nielsen's answer, the saw blade is normally designed to essentially squeeze the material between the teeth and the shoe. This generally makes for a more controlled cut. Circular saws, saws-alls, and most other mechanical saws work on this principle, too. If you were to use the blade you have ...


4

On a mass manufactured part, one solution is to cast the piece and shape the die (with an inside fillet) to form an outside fillet. Of course, if you want your casting to have an inside fillet, you'll need an outside fillet on your die. Assuming you're not casting, and working with a commonly machinable material, external corners would typically be rounded ...


4

For high accuracy over long distances it's typical to use general surveying techniques. You use a total station (like this) which will get you 1.5mm accuracy in a single shot. They're no laser tape measure. Repeated set ups /readings with some statistical corrections should get you easily below 1mm. Note too that these are immune to thermal expansion of ...


4

It seems likely that costs associated with the material prevents economical production of red glass. Rather than a matter of possibility, it may be a matter of viability. Without knowing more about how the glass is produced or the specific materials used for their bottles, it is difficult to say the exact reason. The best answer I can think of is that the ...


4

A "force" in a PLC is the act of forcing a memory bit on or off from the PLC programming software. It is used exclusively for testing. Forcing a bit on or off over-rides all other PLC logic. You can think of it like both setting it and making it read only. "set" a bit is also an option with most PLCs and is also useful for testing. It differs from "force" in ...


4

The main issue is practicality. The vast majority of car buyers have certain expectations in terms of comfort, features and interior space which are pretty much essential in their choice of vehicle. If you want to be able to carry 4 peopel in reasonable compfort and have the ability to carry a sensible amount of luggage then that imposes certain ...


4

Aluminum sections are extruded from billets heated to 800-925F under high pressure and then pushed through a die. During the entire process temperature is carefully controlled, because depending on the aluminum alloy and performance expected heat stages at the beginning and exit out of die are crucial. here is the diagram of the extrusion machine.


4

According to p.33 of this presentation 'bedding in' is a process of packing the molding sand by ramming the sand around and under the pattern until the sand is tightly packed and even with the parting line. There is also a glossary with foundry and casting terms defined here. This is used when the parts to be cast are quite large, often as a step in pit ...


3

I'd recommend approaching this as a two-step process of cutting the shape and then preparing the edges. In my experience the cut edges of 5 mil annealed copper (0.005", about the size you're looking at) are always sharper than I want to be casually handling, even without burrs. It's also a bit of a delicate edge to ease because of how malleable thin, ...


3

Accuracy will vary a lot depending on what you are interested in. At the simplest level you are limited by the layer thickness, which is in the $20-100~\mu m$ range. This places a limit on the accuracy of the dimensions that can be achieved in the z direction. Theoretically you can achieve very high accuracy in x and y, but in reality you are limited by the ...


3

What are tin whiskers? The easy explanation is that Tin Whiskers are tiny threads of tin that grow out of lead-free tin soldier. They are a problem because they can cause electrical shorts at random times. They can begin to grow from weeks to years after a part is produced. The exact causes of tin whiskers are not known, but their growth seems to be ...


3

The average and standard deviation from the above sample set are: Average ($\mu$): 4.754V Standard Deviation ($\sigma$): 0.142368 Mean: 4.74 USL: 5.5 LSL: 4.5 C$_{p}$ : 1.1706 C$_{pl}$: 0.5947 C$_{pu}$: 1.7466 C$_{pk}$: 0.5947 Equations $\text{Pr}(\mu - \sigma \leq x \leq \mu + \sigma) \approx 0.6827$ $\text{Pr}(\mu - 2\sigma \leq x \leq \mu + 2\sigma) ...


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