Original Prusa i3 Mk 2 kit

[Colin Leighfield]

Good one Tony.

[Tony Bennett]

new fan nozzle under way.

Tony B.

[Nev]

Excellent.

If you can do that as a complete beginner (no offence ment) to 3D printing that's great.

Was the fan nozzle a pre prepared file ?

I'm going to download some cad software and have a play (this is just the build up to clicking the buy button you understand).

Well done that man.

Nev.

[Tony Bennett]

Fan nozzle is on thingiverse as a download file.

you have to slice it in cura to get the g code needed for printing, upload it to the sd card nd press print.

sit down and have a cup of coffee while you watch the printer do it's work.

it is mesmerising to watch.

Tony B

[Delta Foxtrot]

Posted by Tony Bennett on 15/01/2017 21:00:20:

well it is built and working.

only printed the test piece so far, but we managed it on the second try.

first try and the bed was too low and it did not stick well.

raised the bed by a fraction and it printed well.

ok the supplied cooling nozzle fell off and will need replacing, but it printed fine without it.

i am now printing a new fan nozzle to replace the supplied one.

so far it all is working well with no major problems to write about.

fingers crossed for future use.

Tony B

Nice to see you are up and running Tony. Is that a bar of soap? Are those holes in the layer? If so I guess a few more top layers would fix that.

[Tony Bennett]

its a bad picture, that is writing sunk into the surface.

Tony B

[Delta Foxtrot]

Thanks Tony! Look forward to seeing how things develop.

[Tony Bennett]

designed and printed my first parts today.

nothing fancy, just a wheel collet for the ensign tail wheel.

i need to tweek the design a tad just ensure the next one has a tighter fit on the axle.

still i am pleased to have done something of my own.

Tony B

[Delta Foxtrot]

No stopping you now Tony, great start.

Which CAD program are you using?

[Trevor Rushton]

Well its now February and according to Prusa's website I have just a couple more weeks to wait. I hope it lives up to expectation when it arrives. Tony, from some of your other posts you look to be getting a bit frustrated with yours?

I'm keen to see how the resolution works out; one of the reasons why I opted for the Original Prusa was that I wanted prints that were as smooth as practicable; it remains to be seen whether it will fit the bill and how I will get on with the long print times.

In the mean time I downloaded Fusion 360 which is an Autodesk Product - you get a free trial month, but its also possible to register as a hobbyist and get a free 1 year licence. I thought that it was just students and teachers that could register for the free licence but that is not the case. Now I have to say that after a huge amount of messing about with TurboCad and Sketchup I have found a programme that seems to suit my method of working. I watched one video on parametric modelling on the Fusion site and everything suddenly fell into place. Sure, you need to work at it but within a short space of time I was churning out designs for an old timer wheel hub and rim, bellcrank and more magnetic clamps. There are several introductory videos on the Autodsk site - well worth looking at those; after that its simply worth having a design in mind and then finding out how to draw it.

One of the problems that I have found with my Stepcraft CNC is that you can produce a drawing, import it into Cut2d to prepare the gcodes and then find that it cuts some but not all of the shapes. I found that I could improve matters by making sure that all polylines were closed, even if this meant going over the drawing again using the chain polyline tool in TurboCad or by using the close polyline tool in Cut2d. Even this does not work in every case - very frustrating. My question is do you get similar problems in 3d printing and if so how do you prevent it?

[Trevor Rushton]

Well its now February and according to Prusa's website I have just a couple more weeks to wait. I hope it lives up to expectation when it arrives. Tony, from some of your other posts you look to be getting a bit frustrated with yours?

I'm keen to see how the resolution works out; one of the reasons why I opted for the Original Prusa was that I wanted prints that were as smooth as practicable; it remains to be seen whether it will fit the bill and how I will get on with the long print times.

In the mean time I downloaded Fusion 360 which is an Autodesk Product - you get a free trial month, but its also possible to register as a hobbyist and get a free 1 year licence. I thought that it was just students and teachers that could register for the free licence but that is not the case. Now I have to say that after a huge amount of messing about with TurboCad and Sketchup I have found a programme that seems to suit my method of working. I watched one video on parametric modelling on the Fusion site and everything suddenly fell into place. Sure, you need to work at it but within a short space of time I was churning out designs for an old timer wheel hub and rim, bellcrank and more magnetic clamps. There are several introductory videos on the Autodsk site - well worth looking at those; after that its simply worth having a design in mind and then finding out how to draw it.

One of the problems that I have found with my Stepcraft CNC is that you can produce a drawing, import it into Cut2d to prepare the gcodes and then find that it cuts some but not all of the shapes. I found that I could improve matters by making sure that all polylines were closed, even if this meant going over the drawing again using the chain polyline tool in TurboCad or by using the close polyline tool in Cut2d. Even this does not work in every case - very frustrating. My question is do you get similar problems in 3d printing and if so how do you prevent it?

[David perry 1]

Had some real headaches with my prusa all of which came down to build issues. So my 3 lads faults.

I am not entirely happy that the software is fully robust but i have to keep reminding myself that the computer in charge is akinto a zx81 i guess.

I found difficulty in getting pla to stick to the bed...pritt stick works wonders

The end result is though the proof...and it is very good. I made the tricerotops head and its immaculate. Im now doing the spitfire andnthat is also very very good.

I increased the nozzle temp, reduced the speed and all is good.

I print the first layers at 10% to ensure they stick. Then ramp up to a higher speed. The faster speeds give a finer finish.

All in all i am delighted with the Prusa, it works fine. Its . Learning curve in leading edge technology.

Id buy anither prusa for sure.

David

[Trevor Rushton]

At long last my Prusa arrived on 14th Feb - exactly when they said it would. First impressions were of a neat and well packaged kit with the parts for each stage carefully packed and labelled.

I have not made very much progress due to other commitments but I have assembled the y-axis frame which is constructed of studding and 3 d printed corners. The lit comes with a printed manual but the photographs are small and unclear - its easier to follow on the on-line version. The instructions are clear for the most part, save that the fixing of the bearings was a bit misleading. Helpfully, the on-line version allows you to post comments so its worth reading those at each stage.

Initial alignment of the parts feels a bit hit and miss but once you have worked it out it makes sense. The key seems to be to get it absolutely right now as its much harder to fix later. I spent ages levelling the four feet.

I will not post any pictures just yet as in reality everything you need is shown on the assembly instructions.

[Delta Foxtrot]

Trevor,
Good to hear that your Prussa has arrived. Mine was promised for the 28th Feb and has just been dispatched.

I have read that getting the y-axis aligned and square is a bit hit and miss. There is a neat jig for this on thingiverse but without a working printer it is a bit chicken and egg. I am wondering if I can make some sort of jig for getting this right.

Look forward to hearing your lessons learned.

Dave

[Trevor Rushton]

Thanks Dave.

The y-axis starts off hit and miss, but you get the correct length by inserting the rods and the correct width by using notches in the metal frame so its not a big deal. I think it probably would be easier if there was a jig, but I don't think its essential (with the caveat that I'm not yet operational).

Fitting the y axis belt was a bit fiddly and took some adjustment but I was pleased to find that the assembly remained true.

The construction makes quite extensive use of cable ties - this felt a bit temporary, but they are quite effective and seemingly robust. I am pleased with the quality of the 3d printed parts; they have fitted well so far.

I finished the y-axis tonight and then assembled the x-axis which presented no particular issues. Assembly time so far circa 4 hours - 2 evenings.

Trevor

[Ian Jones]

Coming along Trevor, looking forward to hearing more .

[Trevor Rushton]

Another couple of hours last night; its starting to look like something now. Assembled the x,ynd z axis and finished the extruder holder. No particular issues; fitting the captive nuts is a bit of a fiddle but if you pull them into place with a suitable bolt first its fine.

Quality of the printed parts is good; they fit well ( I think its because I am unused to 3d printing that I half expected things not to fit very well). The only thing that I am not so sure about is the x and y drive belts - these do seem a bit hit and miss in terms of tension; the belt material is a straight length and you have to join it at a central printed part by looping it around and wedging it. I am not sure if I have got the tension right; movement feels fairly stiff but I have nothing to compare it with. Instructions say it should twang - which it does so I suppose its okay.

Another couple of sessions should see it through unless we have calibration issues.

Trevor

[Delta Foxtrot]

Sounds like you are cracking on with this nicely Trevor.

My Prusa kit is due for delivery tomorrow. l may take a while to build it due a bad back as a result of a fall I had last week.

[Trevor Rushton]

Dave, I hope your back improves soon; nasty things backs; had my fair share.

Another session last night; slightly less rewarding and a bit more troublesome building and fitting the extruder; my problems were mainly caused by a square nut getting wedged in the wrong place and misreading the photographs resulting in misplaced wiring runs. No major issues, just a matter of patience and following the instructions very carefully. As noted in a previous post some of the assembly instructions contain posts sent in by other builders; it is worth reading these but I found that I was not encountering many of the issues so perhaps the kit has been improved.

One small point was that in my efforts to remove the wedged nut (and bolt) I managed to peel off a small lamination of the printed part. Not a big deal but the plastic was surprisingly weak in tension. Once I am up and running I will do some tests - could be critical for some component designs.

Electronics and printer bed tonight.

T

[Delta Foxtrot]

Thanks Trevor.

I found a really good video on YT which discussed printed part design with regard to strength. It was a neat looking vice design which you can also find on thingiverse. Basically you need to consider the orientation of the layers in the printed parts vs what type of loading it will see to get the most out of a given material. Printed parts will not be isotropic and tensile loads are best aligned along the printed layers. Common sense really, but a point well made by the video.

Cheers
Dave

[Delta Foxtrot]

I found the video:

https://youtu.be/mziT7KV-fRI

[Delta Foxtrot]

My Prusa kit just arrived via UPS.

[MaL]

A Prusa i3 here too, although I opted to go for the steel version as I wasn't sure the acrylic frame would stand up to daily wear and tear. Also have a mini kossel which is a delta 3d printer which is even more fun to watch when you think what must be going on in the background to make it work.

I started off using pronterface to control the printer and slic3r to generate the gcode files, both are free from http://www.pronterface.com, but have since moved on to a commercial package. I tried Cura but found it to be too quirky for me. Another free package you can try is MatterControl from matterhackers.com, it also combines the slicer software and the printer control in one package but I found it to be a bit cumbersome also.

Cad package I use is 123D Design from Autodesk, it's the big brother to tinkercad and is also free for non-commercial use

Such an interesting hobby that you tend to forget about going out flying!!

[Delta Foxtrot]

Hi Mal!
I did not notice any options on frame materials for the i3 Mk2.

[Trevor Rushton]

Hi Dave and Times

I did not see a steel frame option either but the frame that came with the kit seems to be quite robust; not exactly sure what it is and time will tell if it is up to the job.

Dave I will have a look at the video; The part that delaminated was simply a raised circular moulding for the bolt head, I should have realised that it would separate easily but being unfamiliar with the materials did not even think about it. You comments make sense regarding the orientation; it will be a learning experience to work out how to align the part to make best use of this whilst at the same time making it printable. For example (and this is probably a bad example) suppose you wanted to make a control horn. To print the horn with say the base at the bottom you would end up with laminations going the wrong way. To avoid this you would say turn the part on its side, but if you do this (bearing in mind I have no experience of this whatsoever) do you then have to use "scaffolding" to support it?