Fair enough.

Well, that could work but the speedups would be sub linear.

The reason is the outer shells tend to be both dense and done slowly with the outermost shell done very slowly in order to get a good surface finish. The inside is usually filled with a sparse hexagonal infill pattern (ofen to a density of only 10% or so) and done much faster.

A matrix like system could certainly be able to speed up the infilling, but I think you end up running in to Amdhal's law quite fast.

I haven't run the numbers however, but either way it would depend on the shape. A large, smooth shape would be optimal (lots of volume) whereas a very involuted shape would see little or no benefit at all.

The heads don't need to be close together as long as you are printing out a matrix rather than line following.

3D printers do line following because head positioning is easier and more accurate than starting/stopping extrusion. Your proposed method would work, except it would produce very messy edges.

The people who did the aircraft maintenance used to howl at the notion of the "water landing" -- because until those guys did it a few years ago in the Hudson, no commercial plane had ever done it and remained intact

Very impressive, but one or two planes have not broken up:

http://en.wikipedia.org/wiki/W...

Of course it's not unimaginable, but a smart watch should do more than the phone that it's paired with.

You mean apart from being smaller and wearable, rather than pocked carried? If so, why should it?

I really don't see the use case for a smart watch that monitors heart rate and body temperature the entire time you're wearing it.

Hm. I've seen the same "TSA gets to go tech shopping" sentiment several times here.

It's not so much as an argument as a fact. Someone elsewhere in this discussion posted a link to about 400 TSA employees being fired for stealing stuff from people's tech luggage too.

The thing is if a large enough proportion don't report it as stolen, then it's worth their while to go theive. Or, sell it on to someone looking for a bargain.

But, apparently I'm not nearly as wedded to my phone as everybody else.

I'm so not wedded to my phone that I'm browsing slashdot from my typewriter. Can we have a tech-person-rejecting-tech pissing contest?

Personally, I only use a candlestick phone, lit buy the light of an oil lamp (using only the finest endangered whale oil). It's quite bulky to fit in my pocket to be honest but the main thing is that sometimes other people, dogs and etc trip over the lead when I'm using it in a mobile fashion.

It doesn't tell the time however. For that purpose, take around a grandfather clock in a wheelbarrow.

Why would anyone want to strap a watch to their wrist if it's not picking up heart rate, body temp, movement, etc...

I dunno? To tell the time?

I can't seem any situations where I'd care about heard rate, body temp and etc enough to wear a monitor. I quite like my decent looking, solar charging, automatically set watch for everyday stuff and a cheap sports watch for sport things.

The thing is there's about 7 billion people in the world and many of them own watches (even if only a Casio F-91W). I'm guessing there's niches for all sorts of different watches with all sorts of different weird and wonderful features.

The idea that it's unimaginable to wear a watch without a heartrate monitor is quite entertaining though.

First world problems.

Since when is having an overbearing and corrupt government, and especially it's petty and beaurocratic employees given a sniff of power, making its citizens lives a misery and stealing their stuff a first world problem?

At least in a 3rd world country, you could bribe the gits into giving your cellphone back. Here they get to keep it (If you don't believe that the TSA employees won't all mysteriously end up with shiny iPhones, then I have a bridge to sell you) and there's fuck all you can do.

Sure it is a stupid rule. But the anger over the current state when you alone are at fault is staggering.

It's a stupid rule yet the victim of it is at fault?

This is a classic case of blaming the victim.

No, the rule is idiotic and this is firmly the fault of the administration at the TSA.

If you experiment with glue, make sure you've solvent handy to get it off again.

Good point. The advantage with going for PVA is it's water soluable. I've not yet had any luck printing PVA though since it's so floppy that it tends to not go through the extruder properly instead preferring to wrap itself round the hobbed bolt. This isn't helped by its very low softening point so much so that just the heat from the motors softens it noticably.

If you have acetone though that dissolves many glues.

First, natural selection does work at the level of species too. Else there wouldn't be identifiable species or the possibility of species going extinct. Darwin wouldn't have gotten far with the theory of evolution, if it weren't for the huge variety of observable species.

Evolution really does operate at the level of genes. The species is more of a macroscopically observable manifestation of a collection of genes plus noise. The thing is a species is poorly defined. You can't definitively tell when two species have formed from one and so on, for example.

Genes on the other hand are much more discrete.

Tried ABS juice once, didn't seem to do much for me.

I've been printing with ABS rather than PLA, since I want to use the acetone fume smoothing trick. It is a little trickier, but it can work very well.

How much did you use?

I had the opposite problem. I had to take the (hardened glass in that case) build plate off, clamp the part in a vice and twist it (wearing very thick gloves). No amount of prying could remove it.

I believe that was with kapton (not bluetape as I previously thought), but I may be mistaken.

The key isto make it very thick (it should be a bit goopy, but have no lumps) and you can apply it when the bed is hot. Basically, whenever you foul up a print, chuck the wasted ABS into the pot.

There should be a really visible layer of ABS film after you've applied it. Having the bed hot makes the acetone boil off so you don't have to wait for it to evaporate. Really slather it on.

Given that I had trouble removing it, next time, I'd probably print it on a raft (bottom layer solid to get good adhesion), so that you can remove it more easily. Also, set the head slightly lower so that it squashes the extruded filament down a bit more firmly onto the (now ABS film coated) base.

I had pretty decent results with that forumula. Good luck.

One of the other posters suggested spraying with bostick of some sort (which I believe is PVA). I've heard other people suggest various kinds of sprays. I've not tried them yet.

You could go old school and do it like a dot matrix printer with 10 heads in parallel.

I was thinking if that was possible. It certainly is to some extent. The mid range printers often have dual extruders (or more). That's usually used for multicolour or multi material (especially support material) prints, but there exist hacks to print out a pair of suplicates simultaneously.

I expect you could print the infill in parallel, but printing the outer shells would be harder since they're generally moulded to the shape.

It would help if the hesds were extremely close together like dot matrix pins, but that wouldn't help for infill since that's usually sparse.

In other words, fine grained parallelism is an interesting problem but I've no idea how to solve it.

Yep. Also, adhesion starts to be a problem at high speed.

The printers can move their parts much, much faster than they print at, and they typically do so when positioning a head without extruding. They can also churn out plastic pretty fast too, though you have to crank the heat way up to get the temperature hot enough for the fastest extrusion.

If that's the problem then a series of pre-heaters could work, but I don't think the raw speed is the problem with these machines.

It's why one does the outer layers slowly. You get better precision that way.

I'm guessing from the description that you're printing with ABS. Is that right? And if so, are you priming the kapton (or bluetape) with ABS juice before the print?

I've found that that helped a great deal except that sometimes the print was rather hard to remove from the base.

Well, I'd much rather write a C backend than a C++ frontend. Look how long the specification is, and it is full of ambiguities (some of them purposeful!).

I'm not sure there are any purposeful ambiguities. But, I'd still rather write the front end. I can more or less imagine how I could write a C++ parser that would pretty much work and not be appalingly slow. Of course I'm fanstasising slightly: I'm sure it would be harder than I expect. However, I know that a remotely competitive optimizer (e.g. half as good as GCC) is far beyond my capabilities.

C and C++ back ends are almost the same, though C++ has more in the runtime than C. I'm moderately sure that I could certainly write a parsed C/C++ to asm back end that would work. It would be very very slow, however.

It would take me a long time to write a compiler I felt confident matched the specification, whereas C is small enough I think I could write a good compiler in a reasonable timeframe.

Depends what you mean bu good :)

I certainly agree that going from nothing to a reasonably conformant, non crashy and somewhat correct C compiler would be vastly easier than the same for C++. But, doing that with one that has a runtime performance of even half that of GCC or LLVM would be I think far harder than writing a reasonably conformant, non crashy and somewhat correct C++ front end.

What makes me think that is a few people (e.g Walter Bright and a few PhD theses on parsing) have more or less written an OK C++ front end more or less single handed. I don't think anyone has written a high perfomance optimizer single handed.

Either way I wish hardware companies would stop pretending they have some proprietary advantage in their deradfully crappy software and stick to making good hardware.