Monday, November 26, 2012

How to re-wind a nichrome wire hot end

Actually this is a pretty fast repair, my print stopped printing at about 10:30, and I was printing again by 1, certainly faster than waiting for a new hot end...

Anyway... here is the process, I thought I'd document the process as the only other hot end pictures I can find on solidoodles support forums are a resistor type, (in the hot to clear blocks thread) there is also mention of a 10Ohm resistor, and my machine appears to be different.

First, how to determine if your hot end isn't hot:
The first you'll probably notice that your extruder is in trouble is that you'll start getting a message appear saying "prevent cold extrusion" this is a limit built into the firmware, if the hot end temperature is below (or reported to be below) 170 degrees C the extruder won't function. that's because the ABS won't be melted, if you ran the extruder stepped at this temperature all that'd happen is the gear would stick, and wear a little grove into the filament, then it won't grip. then when the hot end does come up to temp, it won't be able to move the plastic, the plastic will spend too long inside the extruder hot end, then it'll burn and clog.
so you get the message that your hot end it's hot, have a look at the previous readings for temperature.

If the temperature has suddenly dropped from say 200 down to 0, then you should suspect the thermistor.

If the temperature has steadily declined, then you should suspect that the heater is broken.
Another quick and dirty way to test this would be to turn the heater off. monitor the temperature of the printer and apply an external heat source to the hot end, you should see the temperature rise. -if this happens you can confirm that the thermistor is OK, and it's the heater that's broken.

Having determined that your hot end is broken, you now need to figure out why.
Tools you'll need for this step is a multimeter.
start at the back of the machine,
look at the circuit board, at the bottom you should see two red connectors. you are interested in the one on the left hand side, (marked H in this picture).
unplug that connector,
set your multimeter to read volts.
Tell the machine to turn the extruder on.
measure the voltage at the pins on the circuit board. you should get 12v.
if you don't get 12v, (and everything else in the machine is working), then you've got a problem with the main board.
If you do get 12v here, time to move on to the next step.
leave this cable unplugged, and unplug the hot end part of the extruder. (the red plug in the picture below)

now set your cable to measure resistance, (or continuity) and probe from the circuit board end of the cable to the hot end side of the cable. (you put the probe on one end of the cable, then you have a 50-50 chance of picking the right cable at the other end! so measure both.
there are a few possible out comes here.
Main board connector 1 - hot end connector a = 0 ohms AND
Main board connector 1 - hot end connector b = infinite ohms
This is good. it means that the wire you're measuring is intact and fine.
now check the other wire in the same way.
if the results appear the same, (one wire no connection, the other wire 0 ohms resistance) then the main board to heater part of the set up is working fine.
other possible combinations are:
main board connector 1 - hot end connector a = 0ohms AND
main board connector 1 - hot end connector b = 0 ohms
this means that there is a short in the cable somewhere, perhaps it's been rubbing against the case and the insulation has worn and shorted.
and the last possible combination
main board connector 1 - hot end connector a = infinite ohms AND
main board connector 1 - hot end connector b = infinite ohms
these past two scenarios mean that you need a new cable to go between the main board and the heater.

Assuming that your main board is fine, and your cable is fine.
now check your heater element.
leaving your multimeter on ohms put one probe on each wire.
the hopeful result should be to read a low resistance. elsewhere on this forum, the figure is listed as ten ohms, however, it may also be 6 ohms. (depends on what you have)
anything much less than 6 ohms, implies that there is a short. anything much greater than ten ohm, (like the 16,000 Million ohms mine read) implies a broken wire somewhere.
if you have a broken heater, then you have two courses of action.
buy a new one, or fix your existing one.
fixing it is actually easier than you might imagine.
tools you will need.
A 2.5 mm hex wrench.
a soldering iron + solder
a craft knife/exacto knife
a roll of 1/4" (6mm) Kapton tape.
scissors (for cutting the tape)
1 adjustable spanner (or whatever size your nozzle is)
1 plumbers wrench, (those adjustable pliers type things)
1 length of nichrome wire.
the stock solidoodle uses AWG 31, (however you can change this for whatever you want).
(indeed I'm actually going to recommend changing this -I'll say why later -there are pro's and cons.

Step 1.
cut the filament,
you already have the heater unplugged, now unplug the thermistor (blue) connector. the hot end has now been freed from it's ties.
Step 2
take the extruder assembly from the X carriage, (undo the two hex nuts from the read that go through the X carriage and emerge at two m3 bolts right near to the plastic (peek) part of the hot end.
Step 3
Take the extruder assembly, (the clear plastic part) off of the stepped motor, (the four hex bolts that are equally spaced around the motor.
Step 4 (you require some space here - unless you've taken the extruder apart before plenty of times and know how it goes back together)
Remove the bolt that secures the spring at the top.
place the bolt, small washer, spring, small washer and large washer in a neat row. (so you remember the order that they came apart in.
Next remove the bolt that holds the tension arm in, (your extruder will now only have two bolts holding it together.
carefully remove the nuts from the ends of these bolts, (don't pull out the bolts!!)
now, turn the extruder over.
remove the back piece, put this down on a table, remove the next piece, put this next to it.
remove the two broken pieces, (you'll know what I mean when you do this) and put them next to this. and the bolt that holds the tensioner.
then the two front pieces.
(methodical dissection, clear layout of how it came apart, also take photos if you like! will make it much easier to put this back together.)
you should now have the hot end free from the extruder assembly.
remove the black rubber insulators, (these should slide right off)
find the bulge in the nozzle bolt under the kapton, this is the thermistor.
rotate the hot end away from the thermistor and it's wires and use the craft knife to cut a slit in the kapton, then peel off the kapton and remove the thermistor.
Now use the plumbers vice pipe grips to GENTLY grip the peek plastic, and the spanner to remove the nozzle.
if you find that the peek undoes, but the nozzle does not, then remove the peek, grip the brass pipe (CAREFULLY) and undo the hot end, then replace the peek.
After taking off the nozzle you should find that you can remove the heater element using your fingers.
In order to get to the wires you need to remove the clay that keeps the wires in place.
I used the pipe grips to gently squeeze the clay, this caused it to crumble.
you'll be left with a threaded brass part, with furry wire wrapped around it, (the fur is the insulation)
now check the resistance of the wire, not from where the wires from the plug attach, but the actual resistance of the wire:
you see that the wire is intact, and measures 6 Ohms.
The fact that the wire is intact is a pretty good thing, and led me to believe that the best course of action was to re-wrap the heater barrel.
First, you'll see that the heater barrel is made of brass, (conductive) also that removing the clay has lead to a lot of that furry insulation material going AWOL. so wrap the barrel in Kapton.
then starting at the top, wrap the barrel round and round pushing the wire into the threads to hold them a set distance apart, after the first complete wrap, (well three wraps is what it takes to go top to bottom, add a layer of kapton tape.
then continue wrapping.
next solder the lead from your heater plug to the nichrome wire.
wrap the excess around the barrel and wrap in another layer of kapton tape.
now, before you put it all back together, test the heater to make sure that you read the correct resistance:
reassemble the heater/barrel/nozzle.

then tape the thermistor in place:
reattach the insulation:
and test:

unfortunately, when I tested, the hot end got to about 70 degrees and then the solder joint failed again.
I have a feeling this is because the nichrome is heating to 1400 degrees, and melting the solder connection, so to fix this, I've decided that the wire should be fixed mechanically as well as soldered.
basically the end of the wire should cross over, then fold back and wrap around itself, forming two loops, (basically a variation of a linesman splice.) clearly using wire in wraps is going to reduce the length in the heater, and reduce the resistance, increase the power etc. so I decided that I needed to replace the whole thing
I had a length of AWG28 nichrome wire.
First, measure a 6ohm length of wire, (using a multimeter, unwind the wire and measure resistance along its length until it reads 6 Ohm.
then add a few cm for creating your wraps in the connection.
start by attaching the nichrome to the green heater connection wires. (splicing them with a loop and several wraps) then also solder.
then wrap the wire around the barrel, until three wraps are complete, add a wrap of insulating kapton, and wrap with wire again, then kapton, then wire, and so on until you reach the end of the wire.
when you're done wrap in a few wraps of kapton.
test the resistance to see that it's 6ohms, then reassemble the hot end as above:
I've left the joint poking out the top so that there is a gap between the solder and the heater.
(the nichrome wire heats up well past the point where solder melts, so the simple soldered lap joint, that is actually inside the clay just simply isn't good enough to last the test of time.)
finally test.
when testing increase the heat in small increments.
looking at this:
V = 12 R = 6 (so I = 2)
gauge is 31.
heat in the nichrome = 1400 degrees C, (solder melts around 200)
my replacement heater actually runs cooler. (a mere 900 degrees C)
but there is more wire, (more heating mass), there is less to heat, (no clay = less to heat) so the time to heat to temperature is actually a lot shorter than the time to heat the stock nozzle.

Monday, November 19, 2012

Client / Server Software

In this post, I'm going to do a brief sort of how it works explanation for client server software.

The reason that I'm doing this is that the next coding lesson will be about creating network sockets on Unix/Linux systems in order to create network software.

There is (as ever) a lot of theory that goes into exactly how network connections etc work.

Rather that try to show horn all that into a single project I thought it'd be easier to post some theory first.

So first, we'll define what is a client, and what's a server.

A server in the context of network software is a program that listens for connections, accepts connections and serves content to those connections, (or receives content from those connections).

A client in the context of network software is a program that connects to another piece of software.

The server listens on specified ports awaiting connections,
The client connects to software that it listening on specified ports.

The network model layers
There is a standard for connecting systems, this is a 7 layer stack called the OSI model, (OSI is Open Systems Interconnection)

Each layer serves the layer above it.

This means that no higher numbered level can exist without the layer below it also existing.
(but you can have lower levels existing withough higher levels in your communication.)

The layers of the OSI model are very well documented elsewhere on the internet, it's a pretty broad subject, and I would suggest reading about it by searching for OSI model, It's practically impossible to break down to a simple blog post.

What is important is that the lessons that I'll be posting now will be using Layer 5 -the session layer of the OSI model. we'll be creating sockets that can be either TCP or UDP, telling the sockets what port we want them to listen on or what port we want them to connect to.
On top of the session level is the presentation layer, this presentation layer sorts out how the data is passed to and from the application layer (your web browser using HTTP) to the session layer (where the IP address is applied) and from there passed down to the transmission layer where it goes off into the world. the presentation layer may not always be used, but when it is used, it generally is used for compression or encryption, or translating between different character sets.

Because we will be accessing the OSI model at level 5 what you do at level six is up to you.

for example you could produce a fairly simple encryption protocol by bit shifting characters such that they appear as gibberish to anybody looking at the packets.
hello world >> ifmmp vlsme
then at the other end, your socket receives gibberish, at layer 5, then your presentation layer (layer 6) sorts that gibberish into real text by bit shifting the other way. and then this data is passed up to your next layer.

The application layer.
The application layer is where many common protocols sit. in general these protocols implement a way for your applications to request data from servers.

A web browser for example uses the HyperText Transfer Protocol.
this is a protocol, (an agreed standard) for the transmission of hyper text.

In general it works a bit like this (very simplistic)
you write in your address bar.
your application layer passes to your presentation layer.

access on port 80 and GET ./ (get the default page at this address)

The presentation layer receives this command, and because it's https (secure) it encrypts your request (GET ./). and passes it to the session layer.

The session layer opens a socket connection to on port 80, and passes the data, (which is now encrypted -though the session layer doesn't care all it sees it's a data stream).

If we hadn't encrypted the data then the presentation layer wouldn't have been used at all.

Another thing that is important in these upcoming lessons is that this code will not be portable.

That is that the code will be platform specific, for windows or Linux/Unix systems.

The Linux/Unix software should work on Macs, and will work on raspberry pi devices, but will not work on windows, and the windows software will work on windows, but nothing else.

However the general theory for each is the same.

How socket connections work.
A socket is basically like a data stream, in the same way that we could read or write files, or print to the console using a data stream, we can read and write data to a network socket.

Your server listens on a port, (for a web server this may be port 80).
Your client software creates a port with a random port number, and connects to the server on the service port, it sends information about the port it will be listening on, and it's address
The server accepts the connection on the service port and creates a new port to reply from,
The server send a response from the new port to the client on the port that it established communication to the server on.

The client may then send a message, and the server will respond.

This will be more obvious when I get into the code, but that's going to happen another time.

Monday, November 12, 2012

How to level the bed of a Solidoodle 3d Printer

I'm sure that there are plenty of other printers that can be managed in the same way, but these instructions are based on the process that I've used to figure out how to level the bed of the Solidoodle 2 printer.

To start with you can leave the printer on and you can use the software called Pronterface to move the extruder about, but I do think it's easier to just hit the button in pronterface labelled motors off, and then move the print head about by hand. you won't damage the printer this way, but still be careful!

The first thing to do I guess is describe how the bed it put together.

There is a flat platform on which the bed assembly is mounted, on the underside of this platform is a series of nuts. going into these nuts are bolts that obviously can move up and down in the nuts.

The bolts are threaded through the metal bed and into the bolts.
Between the bolts and the platform that the bed sits on are some springs, these ensure that the bed in pushed as high as it can go on the bolts, so when the bolts are adjusted in and out of the nuts, the bed moves.

There is 1 bolt at the back and 2 bolts at the front.

To start with push the extruder head to the centre and back of the platform.

This is where you're going to alter the front to back level, Adjust the screw that's in the centre at the back until the platform is about the width of a credit card away from the platform, (in fact use a credit card). turn the screw anti clockwise to make the bed higher and clockwise to make the bed lower.

On the Solidoodle 2 you need to use a 2.5mm hex wrench to alter the bed.

Once the level at the back of the bed has been set move the extruder head to the very front and right corner of the print head, this is where you'll set-up the left/right tilt of the print bed.

Once you've adjusted this screw so that the printer head is about 1 credit cards width from the printer move the extruder to the left most side of the front and adjust that side.

Why credit card.
I'm suggesting setting the print head about a credit cards width during the process of levelling the bed because if you aim straight for 0.3mm and the front is slightly higher the first thing you're going to do is scratch the kapton tape when you move the print head from the levelled back to the much higher front.

Having slightly more space between the head and the bed allows you to see that the head is getting closer before it's too late.

Setting the bed height.
Now that you have the bed level you need to set the bed height, to do this the Solidoodle company suggest using a thin piece of card, like a metro card.

However, I think that if you have a set of feeler gauges you should use them, use the 0.3mm gauge.

Home the head in the X and Y axis (which put the head slightly off the bed, now home the bed on the Z axis (this will raise the bed)

Hit the motors off button so that you can move the extruder around.

Carefully move the extruder towards the bed.

If the bed if much higher than the extruder (and trying to move the print head over the bed won't work as the print head will just hit the bed then you need to look to the Z-stop screw at the back, turn it clock wise to make the bed home to a lower height.

Ideally you should have the bed ship with a Z stop set that the extruder won't hit the bed when you hit Z-Home for the first time.

In this case you can move the extruder to the middle of the bed, hit Z home.
insert your gauge in the gap.

If the gap is to big, move the Z-stop screw on the back wall of the printer anticlockwise. then press home again until you have the correct gap between the print head and the print bed.

Monday, November 05, 2012

The solidoodle has landed

This is the 100th blog post, which I find a little surprising in a way first because I started this blog over 6 years ago, and it's taken me this long to write 100 things -surely I should have gotten here sooner!, but secondly because I never really imagined that I'd have so much to say. -surely I should never have gotten here!!

But a better cause for celebration is that my printer finally arrived. (that I ordered in JULY with a promise of 8 - 10 weeks shipping)

Given that I live in the UK and it's November 5th, that also means that my celebration blog post and Solidoodle arrival will be met with actual fireworks, (though technically not for celebrating the fact that I finally have a 3d printer!)

So I thought in the interests of anyone still waiting for theirs, (and anyone considering ordering) I thought I'd write something about my impressions of the printer.
I guess the first thing to do is get the biggest complaint out of the way first.

I ordered my printer on July 13th, and was told that there would be a 8-10 week wait.
16 weeks later I was still twiddling my thumbs...
It was November 3rd when I finally got my printer.
My printer appears to have shipped out of order, and there doesn't seem to be a reason for this, (support have said that the order was not expedited).
From my point of view, I was not an early-order-er. I ordered after the machine was in production and had started shipping.
I was made a promise that it would be 8-10 weeks, then was made more promises via the publicly released shipping updates time after time, that were also broken.

I only contacted support I believe 3 or 4 times, (and one of those times was to ask for a tracking number)
Generally, I found support to be quick to respond, (when contacted via email), but also fast to make promises. Initially their promises about shipping seemed completely at odds with what was being said publicly, (as in they were offering faster shipping times than the already seemingly unrealistically fast shipping notices that were being released), but they did come through on that promise.
my only two problems with contacting support were:
Queries made via the web form on the solidoodle site were completely ignored.
(I know that the queries are monitored as my pre-sales queries were answered using this form).
Secondly, one email was either lost, or ignored.

Thankfully, I've had no issues since I got my tracking number, but I do have to say I am not relishing the idea of having to contact support, not knowing if my emails have gone missing, I'm in a different time zone, (different continent even) so I don't expect instant replies. but that does also mean that if I send a message I won't know if it's lost or ignored for a few days.
So far as the whole experience those are my only two gripes.
and I can sum it up in just one word. COMMUNICATION,

I really hope that communication improves, that is, that communication about shipping becomes more accurate, that decisions that seemingly don't make sense are communicated more effectually. and really, I hope that if emails are going missing with such frequency, that you guys get a better email provider.
The facts are I'm happy with my machine, (as you'll find out as you read below), but given the communication issues, personally I wouldn't recommend buying this printer to a friend. Perhaps when things are settled and sorted, the back order is completely cleared etc, then I'd recommend a friend buys one, but I don't want to be the reason for someone getting caught up in the current fiasco! having to worry about if they are ever going to get their printer, worrying about if they can even believe what the support people are telling them about the printer.
To be honest an extra six weeks wait actually seems a bit trivial (now that I have the device) but it's the lack of communication that really irked me.
Import duties:
For anyone interested, import fees to the UK were £93.22 (~$148 USD) there is no duty to pay on the machine, the fees are made entirely of VAT (Sales Tax) and processing fees from the post office.

Now only the machine:
There have been a bunch of complaints about packaging, and people getting machines that have been broken, support said some time ago that they would be changing the packaging set-up, and I believe that what they have done has been a brilliant improvement.
Firstly, the outside box was a decent size of card, (about 1/4" corrugated) there was no damage to this
the inside of the box was packed about 3" deep in every direction with Styrofoam peanuts.
the printer was then wrapped in bubble wrap.
the plexi-glass door was covered in a brown plastic coating, (from the manufacturer) and so had absolutely no scratches.
unpon taking the machine out of the box...
the print head appeared to be centred, and bubble wrap had been rolled into little tubes which supported the print head, the bed and all the moving parts.
the roll of filament was inside the machine (under the bed which was raised to the top) and also held in place with rolls of bubble wrap.
Shipping the filament inside the box was a great thing for me, if only because it meant that not only did the filament arrive WITH the printer, - so I was ready to go, it also meant that there was no second box to worry about, no second duty fees, no second postal service fees for the import, and no second drive to the post office.
Considering that some machines couldn't get across the states without coming to pieces, and yet with this new packaging regime this printer has managed to get.
across the state, onto a boat, across the Atlantic, (on the storm front of a hurricane), then across Britain, through various depots, etc, this appears to be a huge improvement!)
So for packaging, I can only offer a ten out of ten!

What's in the box:
inside the box, there is a power supply cord. - it's got a European rather than UK plug on it, but that's not a problem the plug on the machine is a C5 connector and so I've plenty of spares laying around.
there is some paper, telling you what's in the box, your order inventory, a sheet saying welcome to the solidoodle family (a nice if not cheesy touch).
There was a small roll of starter filament.
when I say small roll.
there were reports that some people got a test length of a few inches...
like that.
approximately enough to fashion a new teste for a gnat.
however, there was a generous roll of starter filament,

There was no tool kit, (this was listed on the order form when I ordered that I'd get a printer and a free tool kit containing all the tools I'd need -small scrapper/hex wrench/little brush for cleaning the machine)- but I do have more than enough tools of my own.

tools I'd think that a person could want are
1x 2.m mm hex wrench
1x cross head screwdriver (for removing the case)
1x craft knife for cutting and trimming printed stuff
1 x craft knife with chisel blade for popping prints off the platform.
(for day to day use)
and if you have delicate fingers maybe some tweezers.
- I can't say what tools you're going to need to strip down and rebuild your machine because I haven't done that yet!
To set the machine up I used some regular auto mechanics type feeler gauges. these are really cheap.
as for the tweezers, I generally don't have a problem with touching hot things, - years of burning myself with soldering irons appears to have dulled my senses, so i've been pulling and seeped out or built up plastic off the hot end with my fingers.
Weirdly also in the box was a random m3 nut. it was stuck to the doors protective layer.
When I came to remove the case to install the filament, I found that there was an m3 bolt missing. -not an issue I have plenty of these, but does show a bit of a lack of detail.

Set Up:
The software install instructions are remarkably easy to follow. - I followed the ones on the solidoodle website.
They are literally step by step from opening the box to printing, the only thing that was missing was the instructions appeared to go straight from install this software, to this is how you print. ignoring details on how to level the bed.
Levelling the bed is however pretty straight forward. in fact so straight forward I just figured out how to do it myself.
First I moved the X motor forward and back, and hit X home. - it went the right way.
then I moved the Y forward and back then hit Y home, - it also went the correct way.
same approach with Z, when Z finally homed to seemed apparent that had I decided to start with this axis I'd have a hole in my kapton, and a bent extruder.
so I altered the z-stop.

Then we come to the actual bed levelling.
it's easy enough to level the bed, I use proper feeler gauges, (which I imagine made it easier.)
It took about two minutes to level all four corners.
but then I had the idea to run the extruder over the length of the build area, clearance ranged from a very tight 0.3mm to loose 0.4mm not a huge amount of deflection. (I could measure exactly, (either with feeler gauges, or using a dial gauge -which I bought especially for this machine! -but didn't [yet]).

for my test print I decided that I should print something that would be easy to measure, have some height, involve a complex shape (round), and of course something that I could print to appease the missus for the large amount of money that I'd just spend on a toy.
I went with a heart shaped box smile
printing was pretty straight forward, I left everything on default settings, (so there is a raft), the printer zeros to the bed middle, and then prints in the top corner.
-weird, the y axis homing direction appears to be fixed, but not the start position co-ordinates.
printing happens exactly correctly first time.
and second time.
and third time.
and they fit together. smile

the print measures just fine.
default settings, out of the box, the solidoodle seems pretty well dialled in, the round parts seem round.
the width is the 40mm is should be, the wall thickness is 2mm over the whole shape.
the box lid is printed and is exactly the correct size, (a tolerance fit) to the box. and includes a 2mm overhang of 90degrees/0 degrees (depends where you measure from). - which the printer coped with very well.

further printing
printing more things however does show up some problems in this printer.
I don't need a raft for example, but when the raft is removed, I find that it is difficult to ensure that the first layer extrudes properly, a little more pre feed is needed from the default profile, (this also means a tiny section of the raft is also missing, but that never shows up as a problem).
the second problem is, whilst the bed deflection is pretty minute at a tenth of a millimetre, this does mean that printing can become problematic, the middle is raised high, so prints stick here very well, and yet have great trouble sticking at the edge.
Then there is the problem of heating.

Seriously, I feel I need to turn on the machine, then watch some tele, make a coffee, eat dinner then it might just be ready to heat. The bed has the 0 - 100 performance of my first car. (which was French, and shite).
Another issue, the heat does not spread evenly across the bed.
I printed a small round shape with a star shaped hole through it,
at the centre, the print was so warm on the bed that it was distorted. (-but glossy smooth)
at the edges, there was so little heat that it has trouble sticking and strands were clearly visible. -though bed height may have been an issue here also.

Machine Design:
Over all I think that the machine is designed exceptionally well, everything holds together neat and tidy, it's astonishingly quiet, I expected it to be about as loud as a standard ink jet printer, but can happily say it seems quieter, and the noise that it does make is not as monotonous as an inkjet printer either!!
It looks like it'll take some abuse, the steel frame is very well put together, I've not tried standing on it, but I believe the claim that it would support an adult standing on it!
The machine looks deceptively simple, and I imagine will be very easy to maintain.
I think that the strong frame really sets this machine apart from other machines but at the same time it looks like it really reduces the amount of space that there is to work inside the machine. - I mean there isn't a lot of space for bolt on modifications.

So all in all, I'm very happy with my machine.
There are a couple of snags:
The first is that the circuit board is very exposed, in shipping some of the components had bent, I've bent them back, but I obviously don't want to constantly be bending component legs cause they'll fatigue and snap.
A cover will fix this, and this will be high on my list of things to print.
(I'm also going to get some cable management to sort that lot out!!)
Second, the x stop switch leads rub against the side of the case, the case has a rough texture so eventually this will wear through the leads.
as a temporary fix I've put some parcel tape on the inside of the case. this doesn't stop the rubbing, but does at least provide a smooth surface so the rubbing should not be a problem. - though I may investigate some cable routing in the future.
Third, loading the filament is a bit of a mission with the case on. it's not a problem to remove the case, but I'm thinking of installing a hatch in the top for easy access.

Fourth the bed. as I said above, it's not level, does not heat at all evenly and takes ages to come up to temperature. I believe that the fix for this is going to involve.
A relay, a second power supply, nichrome wire, and a sheet of glass.
Fifth and finally.
I'm not completely sure that the pretty sour taste of my first third of a year of being a part of "the solidoodle family" will ever truly leave me.

so all in all.
Is the machine perfect?
No, but it's pretty darn close, and for the money it's amazing...
If you want to print out generic tat -like the heart shaped box then it'll suit your purpose. if you want to try printing small parts with some intricate details you're going to need to fettle things.