RepRapPro Hot end improvements
We've recently made quite a few changes to our hot ends, and have been slowly rolling these improvements out into our kits in order to improve performance, reliability and ease of assembly.
From today we're pleased to announce that every hot end we ship, be it a spare or as part of the kit, will be our new design. The improvements in the latest design are outlined below:
The stainless barrel and brass nozzle have been combined into a one piece stainless steel nozzle to speed up assembly time.
The hot end resistor has now been replaced by a heater cartridge. This eliminates the need for fettling the holes in the heated block, and makes for a much more reliable heating element
We are now having our own custom heatsinks manufactured, with holes drilled by the manufacturer before annodising resulting in a neater heatsink.
All fans now come with colour coded wires for easier assembly.
Double coil spring washers are now included in every hot end kit for height adjustment should you wish to upgrade to a Tricolour machine.
If you have one of our older hot ends and wish to upgrade, the new kit is available on emakershop here.
Since the release of the TriColour and Colour enhancement kits, the RepRapPro Multicolour fork of Marlin has been under rapid development to improve reliability and functionality. Marlin V1.03 is now available and it is a recommended update to all of our multi-colour users.
Recent updates include:
More robust and improved communications between the Master and Slave
Fixed an issue where by the machine would freeze during tool changeover
Fixed a bug where by using the homing offset command (M206) would behave incorrectly
Improved temperature control to ensure the machine fails safely in the unlikely event of an issue with temperature measurement
A reset GCode is now included in the root of the Marlin folder – send this to your printer to restore factory settings.
RepRapPro Marlin 1.03 is available here
Instructions on how to update your firmware may be found here, Both the Master and slave boards need to be updated.
In addition to the above, we have also reorganised our GitHub repository to take account of the release of the TriColour and Mono Mendel. All design files for these machines may be found here.
The previous Mendel has been archived as a Tag here.
A recent paper on laying down graphene for making capacitors by El Cady et al. is very interesting. They coated DVD-sized discs with a colloid of graphene oxide (GO). They then used a LightScribe DVD writer (the type that lets you create your own labels on a photo-sensitised DVD) to zap the GO with the writer's 780nm infrared laser. This converted the GO to conducting graphene.
You can make your own GO (the recipie is here), or you can buy it online (for example here). And it should be straightforward to form a sol/colloid of it using sonication (possibly in an ultrasonic cleaner like this one).
It could then be deposited on conventionally reprapped 3D prints from a specially designed head (for example like this single-drop inkjet or this one) then zapped with an IR laser on the head like this one to convert the GO to graphene. The result would not just be another route to printable conductors - you can make all sorts of active electronic devices including transistors as described here.
Our researches continue...
Today we have released our Tricolour Mendel - an open-source RepRap Mendel Printer designed to work with three colours or three different plastics at the same time. And it costs under $1000 (though shipping takes it slightly over that mark).
This is a new design derived from our tried and trusted RepRapPro Mono Mendel, which has been such a success over the last year.
We have new, more compact extruder drives specially designed to come apart... Wait! - Run with us on this... When the plastic filament being driven is in the drive the filament itself holds the drive together securely. But with no filament in it, the drive dismantles without tools for easy cleaning and servicing.
We have enhanced the widely-used Marlin firmware to allow the addidtion of a slave controller board to drive the extra extruders. And we are using the Arduino-compatible Melzi electronics for both the master and slave controllers.
All in all we think - in terms of performance and price - that this is just about the best multi-colour 3D printer on the market
To find out more, follow this link.
Now that our colour enhancement is out, it will also be possible to use it to print in mixtures of materials with different engineering properties as well.
Measuring the resistance of a short length of conducting
filament extruded from a RepRapPro Ltd hot end. The 1.75mm filament
used as input was made by rolling and can also be seen.
We have been experimenting with putting conducting particles in printing plastic, inspired by this paper:
They used carbon as a filler, which works nicely, but gives rather high resistances. So we tried silver instead (expensive...) to get the resistance down. This didn't work very well because of the shape of the silver particles.
The silver particles are flakes, and the carbon particles are fluffy and dendritic. We hypothesised that the shape of the carbon allows lots of particles to touch each other (or at least to conduct between them synapse-like by quantum tunneling), but gives the high resistance. So a mixture of the carbon to get the geometry of the particles right and silver to introduce short circuits between the carbon projections might work even better.
There was also a problem with the silver when it came to contact resistance at the surface. It may be that the spiky carbon tends to stick out of the surface, whereas the flatter silver ends up with a plastic film over it.
It seemed like mixing different conducting fillers may be the way to go.
So we have tried experiments with a mixture of both silver and carbon, which seem to work better in combination than either on their own.
Full details can be downloaded from our Github repository here.
Finally, another possibility is mixing a magnetic powder into the filament, for which we don't care whether the particles touch or not, of course...
In the RepRapPro Labs
New Year Sale!
Following on from our busiest week ever, shipping our Christmas Mendels and Huxleys, we have now got our spares back in stock on eMAKERshop. We are currently taking orders and we will ship as soon as possible although we cannot guarantee delivery before Christmas.
Within those spares we have a new spares item listed - Melzi Boards!
We currently have a limited number for £89.99 plus shipping.
We would like to take this opportunity to wish all our customers a very Merry Christmas and a Happy New Year!
We are in the last 48 hours of taking orders for our Christmas Campaign.
We only have a few kits left so get your order in quick for guaranteed shipping by this Friday.
Mendel printed parts ready for packing into the kits
Also, if you have not replied to the order confirmation email sent to the email address linked with your Paypal order with your address confirmation and phone number, please do so as soon as possible. Without these details we are unable to dispatch your kit.
RepRapPro Hot end improvements We've recently made quite a few changes ... Read MoreFirmware and Github updates
Since the release of the TriColour and Colour enhancement kits, the RepRapPro ... Read MoreIdeas on RepRap Printing Graphene
A recent paper on laying down graphene for making capacitors by El Cady et al. is very ... Read MoreMore Blog Entries