CAD 3D PRINTING MODEL MAKING

Have any questions or tips and advice on how to build those bits that don't come ready made.
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Bufferstop
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Re: CAD 3D PRINTING MODEL MAKING

Postby Bufferstop » Mon Feb 27, 2017 11:52 am

I've been following (trying to) this with interest, relating it to the daVinci Mini sat on my desk. You have made sense of the relationship between the variables and the hardware, which you really need to know when it comes to deciding what a printer can and can't do. I'm currently putting myself through an intensive self learning exercise with SketchUp and I think I'm just about ready to try my first fully designed model (in parts), having done some exploratory prints to determine minimum dimensions which can be extruded and the best way up to make the parts.
The daVinci Mini may not be the best choice for most modellers, for a start it has a 3D version of Epsons useage chip which prevents the use of third party consumables in favour of XYZ Co's inflated priced ones, but I bought it for around £170 and I calculate that I will be able to afford to buy around 20 spools of filament before I reach the price of the other contender which was the Prusa i3. There's a second factor in my choice, I can use this to find my way around, work out what's what and then if I decide I need something more flexible I have two granddaughters both with frightening IQ's who will seize upon it for it's ability to make solid their imaginings.
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TimberSurf
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Re: CAD 3D PRINTING MODEL MAKING

Postby TimberSurf » Mon Feb 27, 2017 1:16 pm

timbologist wrote:X AND Y AXIS BELTS AND PULLEYS

steps_per_mm = (motor_steps_per_rev * driver_microstep) /(belt_pitch * pulley_number_of_teeth)
On the OrdBot X and Y movement is by a Nema 17 Stepper motor with 200 steps/revolution or 1.8 deg/step, this drives a GT2 toothed belt 2 means the tooth pitch is 2mm, the driver is set for 16 microsteps
therefore
steps_per_mm = ((360/1.8 ) * (16) / ( 2 * 18 )) * 0.90183505855403442555576411741336


It's still not gelling in my brain! Is the stepper motor pulley 18T? I assume the idle pulley is the same size and that the moving frame is attached to the timing belt. Were does 0.90183505855403442555576411741336 come from?
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Re: CAD 3D PRINTING MODEL MAKING

Postby timbologist » Tue Feb 28, 2017 7:39 am

TimberSurf wrote: Were does 0.90183505855403442555576411741336 come from?

Sorry about should have deleted that part, but seeing it is there shall clarify it. what you find is that when you do the actual calibration of the machine you will find there is some variance from calculated to actual movements, so you need a fudge factor to make it move the correct amount :!:

TimberSurf wrote:I assume the idle pulley is the same size and that the moving frame is attached to the timing belt.

The idle pulley or the tensioning pulley what ever may be the case is usually a pulley with no teeth and is just there as a guide. and yes the the moving parts are attached to the timing belt

Bufferstop wrote:I've been following (trying to) this with interest

I'm glad you have found it of interest, It is a bit heavy going but to get the full picture I think it needed to be done this way.
As far as The daVinci Mini goes if it does what you want it to do then that is good, as far as the filament goes it is a real pain, just like inkjet printer manufacturers we sell you a cheap printer but will bleed you when you buy filament. If you make a lot of small things like I do then it lasts a long time and the cost per item is very cheap. When you print big items that use a lot of filament then it can become very expensive.

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Re: CAD 3D PRINTING MODEL MAKING

Postby timbologist » Tue Feb 28, 2017 7:44 am

Hello those that are still with me.

The below is my opinion of it all.
Most printers will have the same accuracy, and repeatability no matter whether it is proprietary or open source, as the mechanics are basically the same. The biggest difference is in the rigidity of the frame that holds it all together.
The electronics on the other hand may vary quite a bit as some have better algorithms for the movement that give smoother and faster operation. But speed is not everything as on all printers the new layers has to have enough time to stick to the previous layers, so to fast is a bad thing.
The extruder's and hot ends vary quite a lot between machines, making some better for larger jobs while others are suited to finer jobs, ones for finer jobs can cope with larger jobs but not the other way around as seen from the figures obtained.
Which means choosing a printer can become quite difficult, you need to know what you actually want to do with it. Generally people buy another printer because the one they have is to small, I have gone the other way getting smaller and finer each time. And pushing the boundaries of what can be achieved.
Those that have seen some of my printed pieces in my other post know what I am up to.
So all I can say is good luck with choosing the printer for you needs.
So that's all folks in this mammoth post.

Will continue posting 3d printer related bits, including how I design things for printing, and some of the strange things I have done with the printers :x

Timbologist

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Re: CAD 3D PRINTING MODEL MAKING

Postby End2end » Tue Feb 28, 2017 8:25 pm

I have been waiting for the "box set" as it were, copying it all down to read it all in one go.
There will no doubt be some questions but thanks for the thorough info Timbologist. :)
Thanks
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Re: CAD 3D PRINTING MODEL MAKING

Postby timbologist » Tue Feb 28, 2017 9:47 pm

End2end wrote:I have been waiting for the "box set" as it were, copying it all down to read it all in one go.


I will put it up as a PDF when I get home tonight, just need to remove the page markers for when I posted it up on the forum.

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Re: CAD 3D PRINTING MODEL MAKING

Postby End2end » Tue Feb 28, 2017 10:02 pm

Ahh even better! Many thanks timbologist. :)
Thanks
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Re: CAD 3D PRINTING MODEL MAKING

Postby TimberSurf » Tue Feb 28, 2017 11:47 pm

Check this out http://www.davesmrs.com/images/BA/gallery/gallery.html
You don't need to buy a printer, just use existing designs or make your own and go through Shapeway.com or UK equivalent
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Re: CAD 3D PRINTING MODEL MAKING

Postby timbologist » Wed Mar 01, 2017 4:59 am

TimberSurf wrote:You don't need to buy a printer, just use existing designs or make your own and go through Shapeway.com or UK equivalent


The amount of things I make I would have to get a second mortgage to be able to pay for the things at the prices they charge :!:
Timbologist

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Re: CAD 3D PRINTING MODEL MAKING

Postby timbologist » Wed Mar 01, 2017 5:28 am

Hi all those of you that have been following my ear bashing with lots of numbers. :)
As promised attached is the full text of my post, made a couple of changes and added a couple of bits.
Please download and share with others that may be interested.
There are probably many owners of 3D printers who have no idea about what is actually happening.

So just download and unzip ( had to zip it as would not accept PDF files.)

Timbologist
Attachments
3D-PRINTER.pdf.zip
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abenn
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Re: CAD 3D PRINTING MODEL MAKING

Postby abenn » Wed Mar 01, 2017 7:16 am

Just found, and read with interest, this thread. My other hobby is radio-controlled model aircraft, and I've been following a 3D printing thread on one of their forums for a while. Very much sitting on the fence regarding getting a printer though, because I'm a dyed-in-the-wool balsa and fibreglass man, but your thread has made me realise the possibilities for my N-gauge model railway.

Reference your recent discussion about the strength of 3D printed objects, if strength in all axes is important you can always 3D print a mould of your object and then cast it in resin. Or even 3D print the object and use it to make a fireproof mould for metal casting.

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Re: CAD 3D PRINTING MODEL MAKING

Postby timbologist » Wed Mar 01, 2017 8:29 am

abenn wrote: My other hobby is radio-controlled model aircraft,

You should have a look at this site they specialise in radio control models that are 3D printed, you buy the model and print it yourself. They have videos of how they fly and video construction guides, I have the Spitfire as yet to build it.
https://3dlabprint.com/

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Re: CAD 3D PRINTING MODEL MAKING

Postby timbologist » Thu Mar 02, 2017 9:14 am

One thing you have to realise about those Shapeways models is they are done with an SLA printer not FFF that I have been talking about.

The SLA printers use a Photosensitive resin that is in liquid form and depending on the machine they can use a laser that is 100 microns or 0.004"
and layer heights of Layer thickness (axis resolution) 25, 50, 100, 200 microns ( 0.001, 0.002, 0.004, 0.008 inch ) so they are very fine.

Like cheese and chalk, the resin is expensive compared to filament and the printers are about 4 times the price.
When I am rich I may buy one but for now I have to stick with what I have and just push it further to get finer resolution.

Timbologist

abenn
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Re: CAD 3D PRINTING MODEL MAKING

Postby abenn » Sat Mar 04, 2017 3:54 am

I have read of some small aircraft models built using hobby-grade filament-type printers, but they don't interest me. Things like cockpit interior details, and dummy engines, okay, but not whole aircraft ...... yet :-)

But model railway scenery does seem like a promising line to persue.

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Re: CAD 3D PRINTING MODEL MAKING

Postby timbologist » Sun Mar 05, 2017 10:04 am

Hi all

This is my latest dolls house project the old Singer Treadle Sewing Machine, first photo is the 3D model I have drawn, The next 2 photo's are what I have printed so far. And the 3rd photo is my first problem, not sure if you can see it properly but it has holes on the top surface and the detail has not printed properly. This was printed on the Ordbot with 0.2 nozzle and 0.1 layer height, what It means not enough steps to get the fine resolution. which is a puzzle as I have got away with it on the rest of the parts as you can see in the other photos. So need to investigate more.

But you can see how I design to print, I make the model from separate piece's so I can print it as a flat pack with the important surface facing up.
Can't win them all. :?

Timbologist

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drawer front bodgy
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