December, 2015 | GI Architects

So i have had a 3d printer for almost one year now and i have been printing with ABS during the whole time. I have noticed however that as i print larger and longer i get some layer separation due to uneven temp. To solve this after some reading i decided to go for an enclosure. Now the problem of plopping the printer in a cardboard box or a wooden box (apart from the eye sore) is that i would heat up the electronics as well and as we all know the cooler they are the better and longer they run/last.

So i went and did my own design which would keep as much of the electronics out of the box as possible. I also wanted:

Something that looks good
Keeps the heat in
Keeps the dust out
Easy print area access
Easy to move
Fit a Prusa i3 Aluminium Frame
The ability to be build in your living room (as much as i like my workshop back in Bulgaria, i don’t have one in England)

The design ticks all the boxes above and we will go over what you need to make this happen.Very important that i designed this for the Aluminium frame Prusa i3 so it will probably not fit any other.

The design

So a little bit about the design before we begin, the bottom panel and back box secure to the printer so that we can transport the printer around (i have driven it back and forth with no troubles). The front box clips on so that when we are printing vibration do not move it around but at the same time can be lifted to get complete access to the print area and front of the printer. While the back area is secure it’s only held by 4 screw which can be removed in less than 5 minutes to get better access for maintenance (like changing the Y motor).

Materials

The first thing will need is the plastic panels, there are many companies which would cut the sheets and drill the counter sink holes for you so i would recommend them rather than you doing it yourself. I would also recommend you use Polycarbonate rather than Acrylic as it withstands higher temperatures.

We need the following plastics panels:

1 x Gauge: 6mm, W:370mm, L:450mm -bottom panel
2 x Gauge: 3mm, W:370mm, L:225mm -front panel side
1 x Gauge: 3mm, W:370mm, L:360mm -front panel front
1 x Gauge: 3mm, W:366mm, L:225mm -front panel top
1 x Gauge: 3mm, W:370mm, L:300mm -back panel back
2 x Gauge: 3mm, W:370mm, L:155mm -back panel side
1 x Gauge: 3mm, W:306mm, L:155mm -back panel top

All the parts need 4 counter sink holes and here are the dimensions:

For the bottom panel:

For all other panels:

Required Parts for enclosure with spool holder:

11 x 3mm Countersunk Machine Screws/Bolts M3 x 16mm
23 x 3mm Countersunk Machine Screws/Bolts M3 x 10mm
34 x 3mm Nylon Insert Lock Nuts
1 x 3mm SILICONE RUBBER SHEET A3
4 x Zippy Ties
4 x M8 nuts
1 x M8 threaded rod (min 20 cm but recommend 25 cm if you are attaching this for the enclosure)
2 x 608ZZ bearings

Required Parts for enclosure without spool holder:

7 x 3mm Countersunk Machine Screws/Bolts M3 x 16mm
27 x 3mm Countersunk Machine Screws/Bolts M3 x 10mm
34 x 3mm Nylon Insert Lock Nuts
1 x 3mm SILICONE RUBBER SHEET A3
4 x Zippy Ties

Required printed parts:

For the enclosure: http://www.thingiverse.com/thing:1144746
For the spool: http://www.thingiverse.com/thing:1218852

Assembly

Apart from looking at the pictures here is a basic guide:

The four small squares with crescent moon are to be attached to the bottom panel first by inserting a nut in the hole then using a 16mm screw. Once secured you can zippy tie the printer (the 10mm threaded rods) to the squares.
The front front and back back panels go in between there respective sides. The top panels cover all three sides.
To secure the panels we need to use the plastic parts as follows:
The four small right angle L shape looking parts go on the bottom inside of the panels. The shorter hole from the right angle edge (22mm) go to the sides panels and the (25mm) go the front/back panel.
The four 3 sides square looking things go on the top inside of the panels.Like above they follow the same 22mm and 25mm hole rule.
The two long parts with slots and crescent moon go on the top front box towards the 2 guides, they each have a part that connects to the top panel.
The back box secures to the frame with the plastic parts on the inside on the right side and on the outside on the left side.
The 3 tiny red parts you see in the photo below (6 from the bottom) need to be stuck down with super glue to the bottom panel at the front. This will ensure when you are printing the front box does not slide out from vibrations.
You can use the Silicone sheet to cover the top hole and half of the side.

Results

Now the big Q, did it work? Absolutely, I no longer get layer separation when printing large objects and lifting from the bed is 99.8% gone, although it was very rare as i am using the Aqua Net Professional Hair Spray Extra Super Hold 3 which does a fantastic jobs even with no enclosure. In terms or temperatures, just with the heated bed i measured 30 degrees celsius inside the box when the ambient temperature in the room was 18. I could add something to heat up the box as all the printer parts are ABS and can stand 80 degrees no problem but for the moment i see no reason as the prints come out very well. I have had a look online and see other full enclosures keeping 30 degrees with only the heated print bed so all in all i am glad this works just as well.

Final Photos and Part Locations

So here is a quick post on how to create a highly available with automatic failover Dynamic VPN in Azure. It can be either S2S (Site to Site) VPN between Azure and On-premises or a VNET to VNET.

Yeah it’s a mouthful :P.

Before we begin if you don’t know how to create a VPN in the Azure Resource manager interface check out the Microsoft post at: https://azure.microsoft.com/en-gb/documentation/articles/vpn-gateway-create-site-to-site-rm-powershell/. So if you ever wanted to have an automatic failover which protects against a vpn tunnel failure in Azure until now it was not possible, but Microsoft has recently introduced a new option when creating a VPN tunnel via powershell which gives us this ability. The property “-RoutingWeight” in the “New-AzureRmVirtualNetworkGatewayConnection” command gives us the ability to set which is the default route for an AddressPrefix. The lower the value of RoutingWeight the higher the priority (ie. 10 is greater than 20). The way this property works is if both tunnels are up the lower value tunnel will be used for that AddressPrefix but if it goes down the secondary tunnel will automatically be switch to as show below. Its important to note that in ARM mode we can create multiple local sites with the same AddressPrefix.

So that was pretty easy but suppose we had multiple prefixes how would it work? Well think of RoutingWeight as firewall rules the lowest one is evaluated first and if the AddressPrefix matches the tunnel is used and processing stop if not continues to the next. As show below on the left we can see how this applies to VNET-VNET VPN tunnels between Azure networks. On the right we see what happens to the traffic when Gateway2 goes down, obviously the traffic for Gateway2 will be dropped as there is no alternative but the connection between Gateway1 and Gateway4 is re-routed automatically.

Unfortunately this type of automatic failover is not full proof as it’s not aware of the links down the line. Let me try and explain this with the diagram below and the following description. Let’s say Gateway2 is up but for some reason only the tunnel between it and Gateway4 is down. Now Gateway4 will follow it’s rules and it will failover traffic for Gateway1 to the alternative but it will termite traffic for Gateway2, with me so far? However while traffic on it’s way from Gateway4 to Gatewy1 will go the correct way, any traffic coming back from Gateway1 to Gateway4 will be send to Gateway2 as it’s not aware of the tunnel problem down the line, which in turn means that packets will be dropped at Gateway2 and communication between Gateway1 and Gateway4 will fail.

Month: December 2015

Prusa i3 print encloser

Azure Highly available Dynamic VPN (Automatic Failover)