Saturday, 12 August 2017

Umbrella brackets

When we had some sun earlier this year I bought a sun shade umbrella for our patio.


The big concrete stand was getting in the way a bit so I've made some brackets attached to the very heavy table.





I managed to bend a spring clip nut back on itself to fit it tightly to the inside of the bracket.


I 3D printed the knob for the M5 bolt.




To protect the pole from the end of the bolt I heated up a strip of plastic and folded it over the bracket with the bolt passing through the outside flap.


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Warping and adhesion issues

Ever since upgrading the 3D printer to the Ultimaker 2+ I've had issues with prints warping and detaching from the build plate.


Today I finally twigged what was different between before and after the upgrade. The 2+ kit came with a calibration card for bed levelling.


I've measured the thickness of the card against the thickness of the paper I used to use. The paper is 0.03mm thinner at 0.12mm thick. Not only that but the new coated card has also picked up a thin layer of plastic in places from the nozzle so the thickness is no longer consistent, at one point is was 0.20mm thick compared to the average 0.15mm. The paper, despite having been in use for two years, does not have anything attached to its surface.


I've gone back to my thinner paper calibration and the first print is still attached to the bed.

I do not use any adhesive on my glass. I keep it clean with an imitation chamois leather and very occasionally degrease it with isopropyl alcohol.


I also made a change to the design of the model to add expansion gaps so that the shrinking plastic cannot pull the full width of the model.



Fusion 360 beginner tips

If I leave this page until I am an expert I will have forgotten what I found difficult when I just started.
Hence this page. As much a reminder for myself as a guide for others.

There are lots of video tutorials on the Fusion 360 site but harder to find are some handy reference pages covering most topics:
http://help.autodesk.com/view/fusion360/ENU/?guid=GUID-18445C60-F9AD-4217-8066-CA48FA11E514


Navigation

I find the use of the middle mouse button for Pan and Tilt unreliable. This is not specific to Fusion 360 I have the same problem in Blender. I prefer to use the keyboard in Blender but Fusion 360 has some very handy buttons at the bottom of the screen which means you can even work with a touch pad.


Click on the Pan and Tilt or the move icons and use the mouse with the normal button. Oddly to exit that mode you have to hover over that button again and press the Escape key.


In addition the top right corner has a cube and you can select the faces or corners or other bits to get a quick rotation to the view you want and it is always clear which way you are looking even if your model happens to be completely symmetrical.

I find that cube the most useful.

Finding your work

This took me a minute or two.


To get back to your saved work you need to open up the left side panel using the icon in the very top left corner as highlighted in the above image.

Making changes

This was fairly clearly documented but worth repeating. When you open up your sketch it will be in a view mode.


To make changes you will need to select the script in the list and select edit.


When you have finished editing and want to see the result in 3D, use the Stop Sketch button.

Selecting Edges and Faces


  • Select one edge or face
    left click on the edge or the face.
  • Select a narrow face
    Zoom in until moving the mouse over the face changes the colour of the whole face. Then click.
  • Select multiple edges or faces
    Hold down CTRL and left click on each element.
  • Select an edge loop
    Double click any edge in the loop.
  • Group faces
    Right click on the browser, choose, Create selection Set.
    Select multiple faces.
    Use the icon on the newly created selection set to assign the faces to that set.
    Use the other icon when you want to select those faces.
Construction

You can add features that are not part of the model but used as the basis for calculating other parts of the model.


Like construction lines in hand drawn work.
This allow you to mark centres and position things parallel to faces.

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Special Care

  • Centre your model about the origin.

Many functions work about the origin or a manually added construction element.
I could not find a way to automatically centre a model on the origin. You can move it manually but each group of faces needs to be selected and moved.

Tip: When you start always create your main section central to the origin.
For symmetrical models that you intend to mirror or rotate, starting with one corner on the origin may be appropriate.

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Things I Could NOT Find

In such a professional looking product there were some features that I expected but that I could not find at all. In many cases I even found feature requests from as far back as 2013 and yet today in 2017 I could still not find the feature!

If anyone knows how to do these please post a comment to let me know how.

  • Repeating Groups of Faces on other Faces [no idea how]

All I wanted to do was have the same feature on each side of a rectangular box.
I can copy the feature as a group of faces and I can copy sketch elements but I could not find a way to use a parameter to repeat a feature on each face.

If I copy the faces I cannot find a way to line up one face to exactly touch another face. I had to rely on the grid snap. I might be able to mirror the features but I cannot find a way to create a exactly central mirror line!


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I will add to this post as I find other features worth noting.

Friday, 11 August 2017

Fusion 360 for 3D printing

I've only been using Fusion 360 for a day and already I am convinced that it is a very good tool for creating models to 3D print.


Autodesk have created an application designed for engineering. The starting point is a sketch, like you would draw on a bit of paper but this is online. You don't need to worry about exact sizes to start with because once you have your starting point you can dimension each edge and the shape adjusts to those sizes, angles and formulae that you enter.


In just a few hours I have recreated a model that I had recently printed. That time spent included learning how to use each feature I needed as I went. I watched a few starter videos and read a few of the beginner reference pages from the AutoDesk web site. The results of just a little effort are already very usable.

Having a little bit of AutoCAD knowledge may have helped because some of the interface was vaguely familiar. Getting my head round the construction and formulaic way of working probably took me the longest.

Unlike the vertex modelling that I am used to with Blender, Fusion 360 is a mathematical construction tool. Create shapes, called bodies, which can be used as part of the finished model or as a construction component to cut away at other bodies to leave the shape you want. Just hide the construction from the finished model. Parts can be kept as separate components or binary joined so they make a single object, ideal for 3D printing.


The construction lines and objects are still there, but not part of the finished object. If you change any dimension all those construction elements remain in the calculations so you can make changes to any part of the model and the finished object adjusts based on the way you have built it.

This makes changing things like lengths and thicknesses very easy.


The end result for 3D printing was very tidy.

I was a little sceptical about using an online application but it is still installed locally and in the event of an Internet outage saves files locally until the connection is re-established.

Files can also be deliberately archived locally or exported to a short list of other file types, if desired.

The only issues I've had probably relate to pushing the USB dock a bit hard. I use that with my laptop. It's not an ideal setup for 3D graphics work but it's done the job regardless most of the time.


Fortunately, for us home 3D printing enthusiasts, AutoDesk have made Fusion 360 available for free to hobby and education users and even very small businesses.


The implication from the wording is that it will remain free otherwise I would not be using it.

Tuesday, 8 August 2017

Socket set continuation

I have continued to evolve the the arrangement and storage segments for my socket set that I started a few weeks ago.

I've tried to incorporate a support shelf for the smaller internal tool cases.
This has led to the spanner rack taking a lot longer to print and I've had a few failures.


I am confident it will print more reliably if I slow down the printing speed. That would mean that as one piece it would now spend two days on the printer.

I'm not keen on such a long time printing. The slightest error and the whole thing has to be started again!


To reduce the risk, I have split it in to two pieces with dovetail joints to hold it together. I have also included holes to allow me to pin it with nails. The nails are probably unnecessary but no harm allowing the option.



I've also added a thin pouch within the handle of the case. This was primarily to help align the case halves when closing it.


It's worked well.

Monday, 7 August 2017

Ride height sensor connectors

When checking under the Discovery, I noticed that the connector housing is missing for one of the air suspension ride height sensors.


It appears to still be working OK so I've wrapped some tape round it for now. I would like to fix it properly at some point so I've been on a hunt for the connector.


It's a quite unique shape. With a little bit of research I'm fairly sure it is from the Micro Quadlok range, see the following from the manufacturer's site:
Housing: http://www.te.com/usa-en/product-1-967616-1.html
Contact pin: http://www.te.com/usa-en/product-1740336-1.html
Seal: http://www.te.com/usa-en/product-967056-1.html


They are available from RS Components with the associated components:
http://uk.rs-online.com/web/p/automotive-connectors/6801464/
http://uk.rs-online.com/web/p/automotive-connector-accessories/7180712/
http://uk.rs-online.com/web/p/automotive-connector-accessories/6802455/
Spelt in two different ways, so it needed multiple searches on the web site:
http://uk.rs-online.com/web/c/connectors/power-connectors/automotive-connector-accessories/?searchTerm=micro%20quadlok
http://uk.rs-online.com/web/c/connectors/power-connectors/automotive-connectors/?searchTerm=quadlock



I've also found a kit on e-bay which will be easier to buy but a bit more expensive:
http://www.ebay.co.uk/itm/Discovery-2-SLS-Air-Suspension-Ride-Height-Sensors-Harness-Connector-FREEPOST/172253397501


The clips that hold it on to the ride height sensor are a pain to get off so I have not yet managed to get the good one off. Once I have one in my hand to see close up, I'll practice releasing the latches before I have a go at the car again.

Friday, 4 August 2017

Filament spool spindle

If you refer back to some of my earlier posts about the Ultimaker and feeding filament, you will know that I think the friction from the spool often causes under-extrusion. I have a further idea to reduce the drag.

Upside down, for printing

This is a spindle for the spool with bearings in. There are loads of designs available that do the same thing. Most involve clamping the spool in some way to a spindle containing bearings.




I like to be able to easily lift the spool on and off. I see no advantage in a complex clamp. At the moment the spools just loosely hook on a fixed shaft. A bit looser than the original clip in spindle which is very fiddly to work with. This design is just an evolution of the hook but with bearings to make the spindle run freely.


This has worked very well the spool spins freely.

Bill of materials:
1x M8x110mm bolt
1x M8 nylon locknut
2x M8 Form A (normal) washers
1x M8x25mm or penny washer
3x 8mm axle 22mm x7mm bearings (from skates)
Optional:
2x 10mm O/D x1mm thick lengths of aluminium tube cut to fit as spacers between the bearings
The 3D printed parts:
1x Hook support
1x Spacer
2x Spindle halves

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