Using a reprap to make adult objects( aka things for sexy times)

Essentually every time that the reprap is brough up as a news story, at least one comment says "it'll soon be used for sex toys".

Yes....yes it will.

It's a simple fact the when it comes to technology, two things really can drive a new technologies development. Violence and sex.

Violence generally is an unpleasant thing by pretty much universal agreement, and frankly the reprap is about making the world a better place. Yes violence gave us better Radar,plenty of malaria meds,jets and nuclear power but we'd rather be avoiding that for the reprap, a sentiment that pretty much everyone agrees on in the reprap community.

And onto sex...it is truely an awesome thing. And people often like a little assistance for either when they're with another person(known by the technical term of "it's business time" or going solo. As long as it doesn't overtake the rest of your life, sex is just an awesome thing generally. And when it comes to assistance, it can sometime cost alot of money and time to find the thing that suits yourself (or your partner) perfectly. Something isn't quite long enough? That Bulge isn't is quite the right place? Just edit the original file and have another go. Thingiverse does not allow sex stuff on it (for a reason, probably so the site won't be thrown in with porn sites on filters)

Anyway, the current reprap is unable to directly make anything thats safe for use inside of a person (outside is another issue, but we won't get into that). So how can it be used. Quite simply in fact. Just print yourself a mould and fill it with the right type of rubber resin or medical grade silicon (there are plenty of website which describe this, source the actual material from them).

Anyway, onto the pictures, I haven't made it yet, but this is a proof of concept. You print two of these and then screw the two pieces together then fill into the open end. It's actually a very short piece, about 9cm long, mostly because I wanted to reduce warping and to make it makerbotable.

The stl file can be found here

Major factors in printing this is:

-Don't bother giving it a high fill, fill it to the minimum that will work and be done with it. I'm having a go at printing with .15 fill and seeing if this works.

-Make sure the whole thing is watertight. I recommend pulling back the speed of your print by 1-3mm because this will make the whole build much more watertight to keep either the silicon or rubber in it's place while it sets. Another method to ensure a solid watertight piece is to adjust your layer thickness. If the piece isn't watertight, try getting the piece and lowering the thickness by .01 or .02 mm. This will often show up as a much stronger bond.

-If you simply bolting 4 of these together you could make a much more reasonably sized piece, simply build a hole along it's long axis would work, though warping would effect it a bit.

-This design is only suitable for vaginal use(if used for that, see next point for my little legal disclaimer). It's base is not flared and thus would be easily lost if use anally

-I offer no guarentees or recomendations for the use of this file. If it's illegal to make or sell sex toys where you live (sadly this is true even in some modern countries) then I recomend you don't do it. Also This is legally a novelty item and for legal reasons I cannot recommend that they get used for their obvious use.

-Have lots of fun with this.

And cos I feel like saying it again....it's business time!

Adjusting PID controller for the heater

The makerbot version 1.6 firmware includes a PID controller. This is designed based on a makerbot extruder, which used nicrome and kapton tape.

I use a combination of 2 5 Watt ceramic resistors and fire cement (all wrapped up in PTFE tape) for my rebuilt BfB extruder(it's hard to find insulated nichrome in Australian electronic stores). Normally if it was running at room temperature I would need about 10 seconds before it started to show any effect in repg and (ie the lag between the ceramic heaters and the thermistor is pretty big) so my range would be around 235-255(probably much higher) for a setting of 250.

Running the PID enabled makerbot firmware I've found that for something with such a large mass and time lag then I needed to adjust the PID settings. The effect was that it would tend to sit about 5-10 degree's below the set point because it would stop driving as hard a little too low. I adjusted the PID settings and now it runs pretty much perfectly, with it floating at 248-250.

The original settings were:

+#define TEMP_PID_INTEGRAL_DRIVE_MAX 110
+#define TEMP_PID_PGAIN 5.0
+#define TEMP_PID_IGAIN 0.1
+#define TEMP_PID_DGAIN 100.0

My settings are:

#define TEMP_PID_INTEGRAL_DRIVE_MAX 120
#define TEMP_PID_PGAIN 8.5
#define TEMP_PID_IGAIN 0.13
#define TEMP_PID_DGAIN 30

Basically what I did was increase the max drive a little (more to make initial warmup a bit faster for me, i'm not running the motor at this point anyway so it won't really have that much of an effect). I then drove the PID more towards a PI controller than a PID. I've found that this controller works when the dominant effect is loss of heat. At low temperatures (I tried it at 150C) then the weakened derivative controller really has an effect and it see saws alot (it really moved around in a range of 135 to 165 and was all over the place). But I've found that at higher temperatures with a lot of heat loss then there is much less fluctuation and the stability is great.

BfB's wiki page on Gcodes already defines an M code which is made to change the PID controller variables. This would make tuning much easier so I'm having a go at simply making these an M code that the extruder can understand with a quick patch to the firmware.

-Peter Hillier

Reprap Firmware and G-code fun (if by fun I mean madness inducement)

Last few weeks I've been printing on and on and on. My main problem has been getting my extruder to work properly. I rebuilt it and now it's working fine. Now a huge firmware/Gcode problem has appeared.

I build and it all works fine...then suddenly at somewhere between 1 and 10 layers in it just stops working. My steppers stop working, but my extruder just keeps running and a huge blog just appears under the stuck extruder. At the end of a normal build the M103 command is sent to the machine which turns off the extruder. What happens now is that the machine just stops. I usually turn it off as soon as I can, though I've left it for 30 seconds during a crash once when I was out washing the dishes during a build.

A vaugely similar problem occured a while ago when using firmware 1.4 in that the machine would turn off the extruder, but keep on working. It was as if the host machine just stopped sending M101 signals. I downgraded to 1.2 and the problem vanished. But even using that same 1.2 firmware this problem just kept occuring. I tried upgrading to 1.4 and the problem just kept on, then I tried doing a run entirely from SD card. I tried this and the same problem occured (though this time it didn't crash until it got to layer 10 or so, while from cable it was crashing at 2-5).

Anyway, given that my extruder has been rather shonky, and I want to make myself a new extruder. This is for two reasons, the first is to take advantage of the nophead developments. summed up, it's better to use steel and a heat sink instead of PTFE. This is combined with a short heating region to make the whole thing work better.

The second reason is to finally get around to running my series of extruder experiments where I mess around with extruder diameter. I want to up the speed as much as I can for printing main parts and I want to see what the effect of a 1mm extrusion diameter is. I've already thought up how to do a strength test and it should be interesting.

A search for materials continues of course. ABS and PLA in australia is difficult to say the least.

Getting the Gcode from 3D to 5D

The main problem with getting this process to work is getting the gen 3 extruder working. It runs via stepper motor that can't be run using the makerbot firmware, or at least it's very difficult and noone on the forums has worked it out. Hense we need to use the normal official firmware Made by Adrian Bowyer and the Bath reprap team. This needs 5d Gcode, which does not have any M code and that data is mixed in with the Gcode. The basic difference is that the 5D code has more processing done before it gets to the firmware. Skeinforge is currently only working in 3D Gcode, and I personally very much like skeinforge and how it works (at least now that I've gotten my head around the program). Erick debruijn  has developed a code that is written in php which converts this gcode into 5d gcode. For the life of me I can't work out how to use the script though. I've learnt how to make a php server that I can run locally (I use WAMP server which is nice and open source, it gives the same result as a closed source program I tried later) but all I can make the php script do is spit out a single out GCode file which is about 10 lines long which mostly has settings listed. I think that I can mess around with the output file name, but searching through the code I can't work out where to put in the input Gcode into the script.

In a completely unrelated area, the artifactory has been set up pretty well and things are now going really well with it all. I'm using our drill press quite alot in making my new extruder barrels.

-Peter Hillier

I'm gonna print more printers

Since I got my machine working properly (as opposed to the rather half working way it used to be working that I assumed was just the way things were) I've been printing parts like crazy. I'm at this moment doing a multpile print, where I print two objects with one press of a button. Once this print is done, I'll have all my Y axid bearing mounts. Oh, and kudos to VIk for redesigning the reprap mounts to make it all much easier to build.

My current findings.

1. The fan is not needed for most small parts. In fact the fan causes huge problems with construction in that it makes parts not bond properly, the side effect being that they will warp very easily as well as tend to detach during printing, but not having the fan running this is avoided. By adding in a cooling time, but not using a fan, the needed cooling is taken care of.by simple contact with the air.

2. When printing, a fill rate of .75 can produce parts that are very very hard. Also useful to know is that by setting the build nozzle size in skeinforge you can alter the strength of parts. Major settings that really alter the strength are.

-The build speed, setting it above your extrusion speed really causes problems with inter-layer bonding. It looks the same as having temperature set too low, but isn't. (According to Simon Kirkby, he had the same effect from when his machine was set to too low a temperature)

-The nozzle diameter setting. Although this would appear to be a physical setting that you just set and forget, it's basic that the higher your nozzle  setting then the fast you build, but weaker you find the resulting materials. If the nozzle is set big then the head rises just enough for the material to spread and when it does it tends to spread out a little, this makes it bond much better then just having the edge of the filament touching.

-Setting to a high temperature doesn't really hurt things, especially when I built my machine to have an ultra rugged resistor heater. A resistor heater is a little more bulky, but is basically much easier to use when heating, given I'm pretty sure that the larger surface area that contacts the melt chamber gives the whole thing lots of energy when operating. Wrapping the whole heater in PTFE (AKA teflon) really helps the thing work well. In order to get higher temperatures, you simply need to mess around a little bit with the firmware heat sensors. You'll find that the original values supplied with reprap gen 3 firmware might be a little off. Simply adjust them a little by getting the mython program on the site and tweak the values a little so that it generates numbers that mean that a certain reading of resistance is assumed to be a reading that is a bit lower. As long as you remember that a reading of 220 is really a readying of 235. This helps you get around the max value of 255 temperature that the firmware has(It probably could be gotten around, but given this is the max of a power of 2, I'm worried it'll cause problems with overflow.

3. The use of the Old solarbotics GM3 (though the one that came with my reprap seemed to have been mis-sized vs a normal gm3.) Has the problem of not lasting very long. Fortunately, while the motor quickly burns out, the gearbox works fine ever after multiple motors have gone through it. I'm still printing a new extruder as a high priority though. I've worked out how to jerry rig new motors pretty fast though, so it shouldn't be a problem in the near future, I bought a dozen new motors anyway online for like $2 each.

Bits from Bytes reprap working

For the past 6 months, I've been trying to get my bits fromy bytes reprap to properly print. I thought I was close to this when I blew my electronics about 4 months ago. Since then I've been trying to get electronics to work and to alter the software to get printing at any level of normalicy.

Today I tried tightening two screws on my extruder by a single full turn.

My reprap now works absolutely fantastically and great, still trying to get the sceinforge settings perfect (it turns out my last months of altering them was wasted time. The first part (a shot glass) I tried after the print worked perfectly well.

So today we learnt exactly why bits from bytes discontinued the version 2 extruder. Because tightening two screws to be about 1 mm tighter can cost you 6 months of wasted experimentation.