Thread: 3D Printing - My rapid prototyping

Originally Posted by Michael G

Some of the mods that people are talking about have me intrigued though - I remember when I first bought a CD player being given a thick green texta to line the edges of the disc because it would sound better. Doing the maths later I think any interference eliminated would have been in the Gigahertz range. Some of these look like they fall into the 'hopeful' category of performance improvements. I'd love to see some comparative figures showing how the changes affect things.

There's definitely a hot rod aspect to it but there's also definite significant improvement.

I catch up with my son (Mike) at least every week for a few hours, staring at working printing 3D printers and talking about 3D printers and IT security are the main activities. Recently this has also been done with new grandson on my knee. Having a quantitative background I constantly ask questions of how much improvement has occurred. Mike also SMS's me many images of the objects and improvements, sometimes on a hourly basis and some of which come it during the early hours of the morning. This is why I know about his progress in a fair bit of detail.

Like hot rods there's still a fair amount of phaphing about.
The position of the filament feed mechanism is moved every time I see Mike's printer and the mother board gets moved almost as often etc.

The Delta was not Mike's first experience with a 3D printer as I gave him my Printerbot to get working.
Mike gave me the Printerbot as a Xmas present in 2015 as a kit and all the instructions it came with was links to 10 , 1hr youtube vids filmed from above the operator so you had to endure the appearance of the scabby balding head of the instructor. Many of the parts in the kit had been printed with a Printerbot and so were pretty clunky.
I suffered the 10 hours of vids and built 95+% of the Printerbot and then got stuck on a triviality (get a small tap and ream out some threads) so it sat in a corner for a year as I had more exciting things to do. Mike got it complete and up and working within an hour of taking it home and after some mucking about with it for a few days, started to print some small new/improved parts for the printer itself. He also ordered a few new parts, partially stripped it down and rebuilt and improved it considerably. The main thing was to enlarge the print area and improved the success rate with better calibration, also the finish improved considerably. He learned a lot from doing this and then decided to upgrade and gave me back the Printerbot and it is back in the same corner as I still have more attractive things to do than use it.

A similar thing happened with Mike's Delta which also came as a kit.
Set up as per the Chinglish instructions and a bit of tweaking Mike could print the usual small test cubes, albeit with a fair bit of wobble in the print.
He had a lot of problems getting the print to stick to the bed which he sorted with advice from various forums etc
The big problem with the Deltas is full size printing in which the delta geometry means that rigidity and calibration is more critical in some ways than standard printers.
One comparative figure Mike gave me was when he first got the printer, even after considerable fiddling and tweaking the initial failure rate on reprinting full base width test prints at standard speed was about one in 3 before it smeared the print.
Using info from various forums Mike was able to improve on that fairly quickly but printing still regressed badly when he tried to speed up printing.
The main problem is his Delta arm linkages had far too much movement (backlash) so could not replicate positions accurately at full width or at higher speeds.
After implementing improvements success rates for full width items is better than one in 10 at about 2X standard speed.
Some simple sections of prints can be printed at more than 3x standard speed with the speed adjusted manually on the fly.
Improvements in finish are also clearly noticeable.

The main "useful" things Mike prints are simple vanilla looking boxes for the IT spooking devices he covertly plants on corporate or govt networks.
The devices include gizmos like Raspberry Pi's, modems and Wifi coms.
With permission from senior management (including an official letter from the top unit manager in his pocket) Mike disguises himself as a corporate or govt IT support person and wanders about in their buildings plugging in these devices.
Then he returns back to his office and Mike and coworkers use the devices to test hack networks from the inside.
The real govt or corporate IT support guys didn't know they were being tested and part of the testing was to see how quickly they could find the devices and manage the penetration.
In the last test of a major Govt department Mike planted 3 devices and their IT guys found 1 device after 24 hours but by then Mike and his coworkers controlled their network.
At that point the Govt IT guys requested senior management if they could shut down their network fearing serious penetration e.g. Russians/Chinese/ISIS.
It is scary how easily Mike accesses passwords and info and how far technical networks are penetrated, even without going physically into offices etc.
The disguising and playing at being someone else is interesting - Mike never ever thought his experience in school plays and musicals would ever become a useful part of his day job.

Oh yes, your feedback is important to me, please provide all complaints in triplicate on the appropriate form and I can assure you they will be provided the appropriate consideration

This is all quite mature technology now. There's bound to be continued refinements, and if they were ever to hit mainstream and be taken up by the average family home when big manufacturers became involved, the prices would of course come way down, but there's no sign of that, and I doubt it will be with this technology. Even if you look at normal paper printers, their prices are distorted by the fact the manufacturers are trying to get you to buy their ink. If it wasn't for that they would be much more expensive, even with the volume they produce. Once laser sintering comes down in price maybe we'll see that 3D technology in the mainstream, but it's still a slow technology at the moment. The speeds are largely governed by the laws of physics, and that's one area where the delta bots mentioned have a slight advantage. They normally have a large Z height too. Something like SLA probably promises the most in terms of improvements in speed etc, but I'm not especially familiar with the resins and how much potential they offer. The thermoplastics we use are of course very widely used in industry, so it's all same same, no different.

Just to clarify, I don't normally pause a print, and definitely won't leave a print on pause when I'm away from the house. If the machine is running I want to be around, even though not necessarily in the same room. I'll set it running and then just go about my usual jobs. It's not just the fire hazard, but occasionally the prints will fail (get knocked off by the head or have a clog etc) and when that happens you finish up with a birds nest. It can all go to hell in a handbag, so I think it's good to be around and check on it from time to time. I know lots of people leave them run completely unattended, it's just not for me. Lots of people don't like to leave their oven on when they're away from home too. Have a look at "3D printing Today" as a blog/podcast. They do very large prints and I know for a fact they change filament mid print, so may be able to offer some clues there. I've never had to change filament mid print. I've also not tried sending commands to the printer while paused. I believe that can be done if you're using USB to transfer from your machine, but that method of transfer is fraught with danger so I print from SD card, which is generally the recommended method. What happens when you pause when printing from SD and then issue further commands I honestly don't know. I think the issue would be to have it return to the point it was paused at. You can insert a pause command in the G code, and if you did that at a specific and known point of the print you should be able to return there. I think the command is M266 IIRC, but check that if you want to try it. Unfortunately I'm being slammed with work at the moment so can't really pursue it, sorry. But let me know how you go, as it would be a good trick to file away if it works. Pausing manually to insert things is fine but of course you need to be there to do it at the right time.

I've had to upgrade the parts for a lot of my printer as it was the usual Chinese quality ie it looked ok, but was in fact crap. The guide rods on mine for example weren't hardened, so wore a groove from the bearings. The good thing about these printers are the parts are very cheap. I think the most expensive thing I've replaced was the hotend, and I have an E3D hotend now, and IIRC that was around $100. I have the original board but ungraded the stepper drivers, the heated bed blew up the first week so that's been replaced, all bearings replaced, the feed tube was cheap nylon and that wouldn't feed the flexible filament well, so that's now teflon, etc etc. Many of the mechanical mods and printed parts are of course free, so I probably have put just over $200 in to this. Not bad considering the amount of work it involved. Yes I think this is mainly still in the geek territory at the moment. If you want a turn-key solution then you probably need to go with an established manufacturer (like E3D) and pay the premium. What you're paying for is essentially all the R&D they've done to get their particular hardware and software running nicely, and they of course need to be paid for that. I hope that present news all works out, as they really are a very good company from my experience. I have a Prusa i3 and being an open source "enthusiast" type background machine, it's unlikely to be just a turn-key solution. I'm keen to see how RC's goes. Once you get everything sorted it becomes just another tool, but people need to understand they're not buying a toaster. I don't think anyone would buy a CNC mill and expect there was a "make that thingie" button on the front of it they just needed to push. Yet that seems to be the expectation with 3D printers. The more you pay the closer you'll get to that, but it's best to still consider them a CNC machine that adds instead of subtracts.

The bed levelling is normally done with just using a piece of paper as a gauge, as mentioned. You have to consider that you do this with the heated bed on if you're using that (as it can distort) and with the hotend hot. So a piece of paper is a good solution. For a single hot end machine the level doesn't need to be perfect, and it's not like you're tramming a mill. Good machines shouldn't change much if all the conditions are the same, but they will need tweaking.

For the bed I normally print PLA on glass, some other plastics on blue painters tape stuck to another piece of glass. So I just swap the glass plates over when I change plastic types. For the glass, instead of printing directly on the glass I cover the glass with PLA from a glue stick. I'd heard Elmers was the preferred one, so that's what I now use and it does indeed seem to work better than some of the other brands. Just rub it on the glass and let the purple haze dry. I keep the glass attached to the heated bed with bulldog clips, so when the print is finished just remove the glass (with the print attached) and pop it in the freezer. The print will pop straight off after its frozen (there's little thermal mass so it doesn't take long), and then you just rub a bit more glue stick on and clip the glass back on the printer. After a while you'll need to wash the glue stick off, so just rinse it off in the sink and then apply some more from scratch. The glue stick itself lasts a long time and is cheap.

Originally Posted by BobL

In the last test of a major Govt department Mike planted 3 devices and their IT guys found 1 device after 24 hours but by then Mike and his coworkers controlled their network.
At that point the Govt IT guys requested senior management if they could shut down their network fearing serious penetration e.g. Russians/Chinese/ISIS.
It is scary how easily Mike accesses passwords and info and how far technical networks are penetrated, even without going physically into offices etc.
The disguising and playing at being someone else is interesting - Mike never ever thought his experience in school plays and musicals would ever become a useful part of his day job.

Having done a real pc computing course back before computers were common place, I find it scary how much top level information is stored on networks with internet access. The only way to keep this stuff safe is to disconnect from the internet. If one person can access it, then anyone with appropriate knowledge can. All these governments/companies are fooling themselves. Physical security is the only way to protect it. When will these idiots learn.

Regarding this thread, it seems to be very popular. It is a subject that interests me. I don't know if it is something I want to get involved in or not. The drawing aspect concerns me somewhat. Years ago I would have jumped in, but now I have more than enough to do. Maybe one day.

Dean

3D printing isn't for everyone that's for sure. As mentioned, I think a good way to think of it is similarly to CNC machining ... because it is. The only real difference is conventional CNC machining removes material to create a job, whereas 3D printing adds material. So for anyone not too sure where they sit with all this I'd suggest if you have no interest in computing, CAD, CNC machining, etc, then do yourself a favour and don't waste your money on a 3D printer. That's not to say you need to actually know anything about any of the above, merely that you have a curiosity in those areas and a willingness to learn and explore more. If you don't have an interest it would be a tough gig. If you have no interest in the process yet really need it to fulfil an actual need, then you'd want to definitely go with a higher cost.brand name machine. If you don't mind getting your brain dirty, then a kit can save a lot of $$$, but it can be a steep learning curve.

I'm not suggesting that somebody should be interested in it, or is in some way inferior if they're not, we're all different and some people just aren't interested. That's fine and nothing wrong with that. The issue is 3D printing has been hyped up by the media, and there's a heck of a lot of BS out there. You would definitely want to do your homework and decide whether the technology as it stands at the moment (mainly FFF/FDM) will fill your particular needs, personality, budget and interests.

Originally Posted by Oldneweng

Having done a real pc computing course back before computers were common place, I find it scary how much top level information is stored on networks with internet access. The only way to keep this stuff safe is to disconnect from the internet. If one person can access it, then anyone with appropriate knowledge can. All these governments/companies are fooling themselves. Physical security is the only way to protect it. When will these idiots learn.

You would think so but I didn't perhaps make it clear that the exact purpose of Mike disguising himself as an govt IT guy, physically entering their building and patching devices into their internal network shows how easy it is to get stuff from a closed a network. The device connected their internal network which they though was physically isolated, to the internet via the independent Wifi and broadband wireless built into the implanted devices. After leaving the building Mike was able to sit in their small visitor carpark and download sample of sensitive information. He couldn't stay there too long without arousing security so he then went back to home base and they accessed more of this stuff via direct broadband connection.
The devices that were implanted were sort of gaffer taped together and together with a pair of Wifi aerials clearly looked suspicious so they should have been easy to find.
Mike has also 3D printed copies of standard mains power expander boards complete with these devices embedded inside them that would be MUCH harder to find.

Forgot to mention that the internal physically isolated network had security that was not worth a dime. The first thing Mike looks for on big networks is old unpatched PCs left on the network. He quickly found a old Windows NT server that he hacked in about 30 seconds and that's how he got admin level access to the internal network. The Govt Dept obviously thought that because the network was physically isolated they could be sloppy with security but it just goes to show. There's a lot more to this story including the bit where Mike was wandering the hallways looking for a likely internal network point for a device. After a while he found a large carrel space with half empty carrells. While plugging in one of the devices he had to crawl under the carrel - while doing that he overheard the worker in the next carrel doing one of those "on-line courses" , on IT security.

Originally Posted by Pete F

3 The issue is 3D printing has been hyped up by the media, and there's a heck of a lot of BS out there.

I plan on printing a 50BMG automatic rocket launcher with nuclear tips first up. I know you can do it the media told me so.

Does anyone have any tips on what sort of plastic filament to buy and from where? I am thinking to start with I will also make some simple small storage boxes with lids.

With regard to leveling, the Prusa seems to have embedded magnets or perhaps it is just some round metal in the bed that it uses for automatic bed calibration. It checks the bed prior to each print at nine points via a inductance sensor mounted on the head. The software driving the printer seems to be an important part of why people are saying it is a good low to middle end machine.

Originally Posted by Pete F

3D printing isn't for everyone that's for sure. As mentioned, I think a good way to think of it is similarly to CNC machining ... because it is. The only real difference is conventional CNC machining removes material to create a job, whereas 3D printing adds material. So for anyone not too sure where they sit with all this I'd suggest if you have no interest in computing, CAD, CNC machining, etc, then do yourself a favour and don't waste your money on a 3D printer. That's not to say you need to actually know anything about any of the above, merely that you have a curiosity in those areas and a willingness to learn and explore more. If you don't have an interest it would be a tough gig. If you have no interest in the process yet really need it to fulfil an actual need, then you'd want to definitely go with a higher cost.brand name machine. If you don't mind getting your brain dirty, then a kit can save a lot of $$$, but it can be a steep learning curve.

I'm not suggesting that somebody should be interested in it, or is in some way inferior if they're not, we're all different and some people just aren't interested. That's fine and nothing wrong with that. The issue is 3D printing has been hyped up by the media, and there's a heck of a lot of BS out there. You would definitely want to do your homework and decide whether the technology as it stands at the moment (mainly FFF/FDM) will fill your particular needs, personality, budget and interests.

In general I agree with what you say, but I did have the feeling when reading this that there are other ways to look at it. I don't want cnc equipment because I only do metalworking because I enjoy it. I have used big cnc lathes and mills. That is just not what I want to do. I still think there is the possibility that I could get involved with 3D printing, someday.

Originally Posted by BobL

You would think so but I didn't perhaps make it clear that the exact purpose of Mike disguising himself as an govt IT guy, physically entering their building and patching devices into their internal network shows how easy it is to get stuff from a closed a network. The device connected their internal network which they though was physically isolated, to the internet via the independent Wifi and broadband wireless built into the implanted devices. After leaving the building Mike was able to sit in their small visitor carpark and download sample of sensitive information. He couldn't stay there too long without arousing security so he then went back to home base and they accessed more of this stuff via direct broadband connection.
The devices that were implanted were sort of gaffer taped together and together with a pair of Wifi aerials clearly looked suspicious so they should have been easy to find.
Mike has also 3D printed copies of standard mains power expander boards complete with these devices embedded inside them that would be MUCH harder to find.

Forgot to mention that the internal physically isolated network had security that was not worth a dime. The first thing Mike looks for on big networks is old unpatched PCs left on the network. He quickly found a old Windows NT server that he hacked in about 30 seconds and that's how he got admin level access to the internal network. The Govt Dept obviously thought that because the network was physically isolated they could be sloppy with security but it just goes to show. There's a lot more to this story including the bit where Mike was wandering the hallways looking for a likely internal network point for a device. After a while he found a large carrel space with half empty carrells. While plugging in one of the devices he had to crawl under the carrel - while doing that he overheard the worker in the next carrel doing one of those "on-line courses" , on IT security.

I did not say that physical seperation would protect it, only that it is the only way. I did understand exactly what you meant. I should have been a bit more specific. The physical seperation I was thinking about was along the lines of the secure, encrypted email service I have just signed up for. Designed by people involved with CERN and housed under a mountain in Switzerland. The physical security your son is dealing with is no better than openly hosting it on the net. Another reason for calling them idiots. They have no idea.

Dean

Originally Posted by Oldneweng

The physical security your son is dealing with is no better than openly hosting it on the net. Another reason for calling them idiots. They have no idea.

Dean

Sometimes they do have an idea, just they're constrained by policy or circumstance.

Example 1: lock the network down by registered MAC address. Then have screams from the science/engineering group about not being able to install/configure new hardware on a 24x7 basis - which was *essential* not just a wish-list. Of course you can also fake MAC addresses anyway, so it's not a panacea.

Example 2: Insist on running Windows operating systems when they're about the worst thing you can run from a security POV. The science/tech people ran mainly unix variants but were always getting hassled to comply with 'corporate IT policy'.

Anyway having lived through it all as first a scientist/tech in various CSIRO divisions and later as an executive level manager in the APS, I don't want to re-live it now. It's all a long way beyond my knowledge base and even further beyond my care factor level these days.

PDW

Dean I don't know what experience you have with IT security, it sounds to be quite extensive having judged the people involved "idiots". I personally don't have any experience on the software side of things, so will have to take your word on that, but many years ago declined a job as a "service engineer" with a BIG commercial hardware provider who supplies the big guns in this field, and I would hardly describe the people I met as idiots!

Just to reiterate again what I said, it's not necessary to have knowledge of computers, motion control, CNC etc in order to run a 3D printer. But if that's the case then you'd be best to buy a turn-key type solution, and understand that you will need to pay more for that. On the other hand if somebody tries to nickel and dime the situation and buy a cheap kit thinking it's just getting same, I'd suggest they will struggle unless they are prepared to invest a lot of time in effort in learning how the whole hardware and software works.

In my case that's exactly what happened to me. I bought a very cheap Chinese kit because, according to the logic of many here, it will be "just the same". It turned out to be a complete POS, and wouldn't even produce a viable print out of the box. Apart from all the hardware I replaced as mentioned, I also had to completely re-write all the firmware, having first learnt what it was I was actually trying to achieve! It was a very steep learning curve, and one I'd like to give others a heads-up on lest they have the wrong idea, but maybe I'm just another "idiot".

Richard I'd suggest PLA to begin with. It's a plant sugar derived plastic so smells nice when it's printing (a bit like maple syrup). It's a good all around plastic and what I mainly use. Other plastics will have other properties that will be better, but I think this is the best place to start.

Originally Posted by PDW

Sometimes they do have an idea, just they're constrained by policy or circumstance.

Example 1: lock the network down by registered MAC address. Then have screams from the science/engineering group about not being able to install/configure new hardware on a 24x7 basis - which was *essential* not just a wish-list. Of course you can also fake MAC addresses anyway, so it's not a panacea.

Example 2: Insist on running Windows operating systems when they're about the worst thing you can run from a security POV. The science/tech people ran mainly unix variants but were always getting hassled to comply with 'corporate IT policy'.

Anyway having lived through it all as first a scientist/tech in various CSIRO divisions and later as an executive level manager in the APS, I don't want to re-live it now. It's all a long way beyond my knowledge base and even further beyond my care factor level these days.

PDW

Good points. I am glad you said sometimes.

It is all indicative of the way we have evolved into an impossible position.

Dean

3D printing is coming of age, the driving force is not the cost of the parts being printed, but the convenience and flexibility to produce unique parts that are tailored to a specific need. My son and I build a makerbot years ago, and that experience was vital in his work with more advanced 3d printers in Austria later on. Here we are 7 years down the track and he's designed his own purpose built 3d printer for printing on fabric up to 1m x 1m.

I look at 3d printers from the view of rigidity speed and accuracy. and shudder before walking away, the are all flimsy, slow and inherently cheap. I wouldn't mind having a go at putting a print head on the CNC mill when it's up and running (soon).

Stepper motors are slow and liable to drop steps, but they are easy to drive and that outweighs the disadvantages of open loop, there is a group who have come up with a way of driving stepper motors like a sort of brushless DC, with magnetic encoder feedback, They have a kickstarter project https://www.kickstarter.com/projects...strial-servo-m or google Mechaduino

Drifting OT, internet security is becoming a bigger issue these days, but if the battle comes down to a battle between encryption and decryption, my money is on the encryption side of the battle. If you have data worth protecting you should encrypt it.

Bob's pen testing son would get nothing from sniffing networks if the traffic was end to end encrypted. he might scan and hit a few vunerable ports from being inside the DMZ, but such scanning is detectable with readily available tools like snort and any number of IDS systems.

One of my earlier jobs was securing factory control networks, and beating off the numbskulls who wanted to connect PLC networks to the corporate IT network without adequate protection. As Dean said sometimes these IT types have no idea!

Ray

Originally Posted by .RC.

Does anyone have any tips on what sort of plastic filament to buy and from where? I am thinking to start with I will also make some simple small storage boxes with lids.

If I had my time over I would start with one roll of black Torwell PLA in 1.75mm. I print it at 196 degrees with the bed on 55 degrees and a bit of UHU stick. It produces wonderfully smooth layers with really good adhesion. All the black prints in my previous photos are Torwell PLA. You can buy a single roll on Ebay easy enough - or go direct to the factory and get it for half of nothing. That said a minimum purchase order of 8 rolls does apply. It would have saved me a heck of a lot of messing around had I steered clear of some of the name brands and went for this stuff first up.

I will take a photo of my DRO arm extension in a couple of days. It's Torwell PLA and strong as heck. I can't break it by hand and therefore I trust it to hold my DRO screen - which it's done without issue.

Originally Posted by Michael G

Mind you, looking at the design and the way parts have been made I do wonder whether they have had a serious look at the mechanical side of the design.
(Except for my lack of income, I'm almost tempted to get one just to show how much they can be improved )

Originally Posted by RayG

I look at 3d printers from the view of rigidity speed and accuracy. and shudder before walking away, the are all flimsy, slow and inherently cheap. I wouldn't mind having a go at putting a print head on the CNC mill when it's up and running (soon).

Stepper motors are slow and liable to drop steps, but they are easy to drive and that outweighs the disadvantages of open loop, there is a group who have come up with a way of driving stepper motors like a sort of brushless DC, with magnetic encoder feedback.

Originally Posted by Pete F

Apart from all the hardware I replaced as mentioned, I also had to completely re-write all the firmware, having first learnt what it was I was actually trying to achieve!

The trouble with you guys is that you wave temptation in someone's face...

So if not using stepper motors, what would you use to drive them? - or given the cost of glass scales is it better just putting scales on the machine and using those for location purposes?
Designing (and making) a sturdy 3 axis platform should not be all that difficult. The main problem is the 'cheap' part - making something out of thin cardboard (ie MDF) is wonderfully 'hacker' and cheap but there are better ways of getting rigidity.
What are other's thoughts - is it better to have a platform that moves away from a print head or a print head that moves away from a platform?

Michael
(being distracted in speculation from all the other things he should be doing... again.)

Originally Posted by RayG

Bob's pen testing son would get nothing from sniffing networks if the traffic was end to end encrypted. he might scan and hit a few vunerable ports from being inside the DMZ, but such scanning is detectable with readily available tools like snort and any number of IDS systems.

Most of the weaknesses come from humans, and very weak password protection. In a recent corporate test (500+ employees), after testing over 3 successive years and each year schooling their IT managers on where the major weaknesses were (and assuming the staff were also schooled) Mike was able to obtain ~40 IT account details by simple phishing emails. He used a two pronged attack, one email targeting lower level staff and one couched in more corporate speak targeting managerial staff. Proportionately he obtained more account details from managerial staff, several of which also had access to sensitive areas of the IT system they should probably not have had. A third attack was based on an automated high frequency surname/first name routine to obtain usernames and then assuming users were still using dumb passwords like "Password1" . Within 24 hours they has full access to their IT systems.

Only about a half dozen staff reported the phishing emails to the company IT support staff and by the time they sent out a do-not-reply email to all staff (and who wants to read IT support emails anyway) it was too late.

Originally Posted by Michael G

The trouble with you guys is that you wave temptation in someone's face...

Not me, they point out all the reasons why I'm not ready to put my hand in my pocket. I already have enough projects in the queue to keep me busy until I'm 150 without accepting any new ones.

A printer that could embed various bits of stainless for boat fittings would find a home in my shop pretty damn quick. Got to work out of the box, though.

Might have to grovel to variant22 to make me some custom enclosures for Raspberry Pi's though. First check if there are waterproof cases already available....... eBay here I come. Again.

PDW