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3d printing with elegoo mars
Ilfracombe in 00 - Progress continues...For my birthday, my lovely girlfriend was strong-armed into getting me a Resin 3D Printer. After doing some research I decided that a good entry one would be the Elgoo Mars which at the time was selling for under £200. This type of 3D uses a vat of resin and cures the layers via a UV light. The model attaches onto the build plate and the 3D print is slowly layer by layer pulled out of the vat of resin until the print is complete and your left with your object upside down. This is known as SLA which stands for Stereolithography apparatus. This differs from PLA printing where you use a spool of material, that is heated up and built onto the build plate, by a nozzle in layers.
First off you need to have a file to print. These are known as STL files as that is the file format the 3D printer recognises. These can either be sourced online via sites such as thingiverse.com where creators upload their designs, some for free and some paid for. Alternatively, you can learn to draw and design things yourself, like I have done to create bespoke items.
Take for example this canopy support at Ilfracombe. I first look and see how the various components could be broken up. The brackets will be one, the fluted base another, and finally the column.
I use Sketchup Free online as I don’t have to pay anything for it and there is plenty of videos on YouTube so you can learn the basics and work with the limitations of the free version. There is other software such as fusion 3d however they are paid for. If you were going to design something really complex you might need these but so far, I have got away with using the free version of sketchup.
All the components drawn into sketchup. I’ve added slots and supports for everything to fit together rather than just gluing it all together with butt joints.
Scaling can be tricky, but I use a scale ruler to try and work out sizes and once printed you can eyeball it to see if it looks right. The software does allow you to be very precise however so if you have dimensions for the thing you are drawing you can just draw using them at full size and scale the model at the end of the process.
It is important to note that at this stage the software sees your drawing as several lines and faces. Once you are happy with what you have you either need to group them into individual components or as a group. This avoids complications later in the process where the slicing software or 3d printer can get confused. Sketchup then allows you to export the file as an .STL file to your computer.
We now use a programme that comes with the 3D printer but is also a free programme that you can download without purchasing called CHITUBOX. This programme lets you prepare the file you have creating for 3D printing by letting you add support material to aid your print in coming out without any defects and edit your 3D model. When importing your model into the software it sees the design as a solid object and will print it as such. Somethings this would be a massive waste of resin and would make the object awfully expensive and heavy to print with a much higher chance of failure. The software therefore allows you to hollow out your model if you want and add drain holes for the liquid resin inside the model to drain out.
The model as drawn now in the slicing software. First up the components need angling around 30 degrees as this allows more support structures to attach to the model and will ensure a more accurate print.
The software allows you to add light medium and heavy supports. And will automatically do this for you. Bear in mind light will leave less marks when you come to remove the material however the heavier supports will support the model more therefore ensuring you do not get a failed print. In this situation I used medium auto supports.
Auto- support is a good tool when getting started however its not perfect see here where it has missed the corner of the bracket. You may get a warped corner, so I manually add in a light support where the green line is to ensure this does not happen.
Once happy with the supports its time for the software to doing some slicing. This is where it works out how it will print each layer of the model. As you can see by these screenshots, we first have the base layer which will stick onto the build plate. This layer is exposed much longer than the others to ensure it adheres properly. On another layer we see where it is creating the supports as well as the actual model. And finally, near one of the last few layers we see the model being completed. On the right you also get an indication of how long the print will take and the cost estimate. You can add in the cost of the resin you are using, and it therefore works this out for you. All that is left to do is to save the sliced file onto the memory stick provided with the Elgoo Mars and you are ready for printing.
So, you just stick your memory stick into the back of the 3D printer, select your file, click print, and off it goes. Now its time to wait and see.
This shows the model upside down on the build plate once printing has completed. You then get your rubber gloves and mask on as the resin is not great for your lungs or your skin. The build plate unscrews from the machine and you use the included scraper to detach the print and drop it into a tub of 99% isopropyl alcohol. This washes off all the remaining wet resin. Next dunk the model in a water bath to ensure that all the remains of the resin are gone. At this point the model is still not fully cured so be careful when handling.
Finally, you need to cure the model this can be done naturally by leaving it in the sun therefore soaking up the UV rays or I use my mums UV nail curing light. A couple of minutes and the model is all cured. You can then gently pull the model / use the sprue cutters to remove your print from the support material and then clean up any marks by sanding or a small file.
It has taken a couple of adjustments to the design to get everything printing perfect and all the parts fitting together but that is the joy of having your own 3D printer. Previously I have designed parts and sent away to have the printed only to find that they have had some error when printing that could not be adjusted. In the background you can see that I have also 3D printed the concrete plinth to the wind break at Ilfracombe.
I hope this article allows people to get an idea of the process that is involved and encourage others to have a go. My next plan involves using a camera to 3D scan objects and people in the same vein as Modelu and then I will be able to print them too.
Cheers
Pete
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NHY581's wagon weathering
The Sheep Chronicles : These are the adventures of a Sheep, the Works Forecat and Naughty George,23 hours ago, SteveyDee68 said:I'm going to be very annoying, Rob, and ask if you've detailed how you went about weathering this wagon earlier on your thread? (Well, there are a lot of pages!!) I just picked up three of these off eBay (two of which require replacement buffers) to go with an old Airfix/GMR version (from my teens!) and would love to achieve the kind of finish you have on this wagon.
Shame Project X won't feature a wharf - I was looking forward to seeing you do water!
Steve S
Morning Steve,
No worries. The modelling stuff does get submerged at times and its a big old thread.
Here's a repeat of a series of images from earlier in the thread. I use the same principles for any planked wagon.
The victim of this occasionis a Minerva 5 plank GWR open.
Here it is, out of the box.
Humbrol Dark Earth acrylic was sprayed over the underframe, lower body and ends.
The inside was worked on first using powders. My pallet is limited and I use only Humbrol powders at present.
The colours used are
Black
Smoke
Rust
Iron Oxide
Sand
Dark Earth
White
All are applied using a selection of really cheap and nasty make up brushes from Amazon.
No particular order. Just add until it looks right to you.
Once happy with the resulting blending and adding of the various colours, they are sealed using Humbrpl matt acrylic varnish from an aerosol.
A light touch is needed. Too wet and you will lose the shades you've worked so hard to acheive.
Once dry, minutes really, I then take to each individual plank with a fibre brush and remove some of the finish until it looks about right. I then re seal with another dusting of acrylic varnish.
I then moved on to the outside. I deepened and distressed some of the planks using a sharp pointy thing.
Then added powders starting with black to infill the groves first. Sort of pre-shading..
Iron oxide was added to the metal work, body and underframe, as was rust and some sand to highlight rust patches.
Smoke and dark earth was used to tone things down.
Again, once happy all sealed using matt varnish.
Again, individual planks were distressed using the fibre brush.
A final coat of varnish and you're done.
I do however come back to it after a few days with a fresh pair of eyes and tweak if required.