Printed gears

The final stage of creating these cogs was to print them out and see if they worked properly as real objects. This experiment has been moderately successful.

The first attempt was the set on the left. Once assembled, the large and medium cog worked together quite well, when I added the small cog the set didn't really work as well. The first problem I ran into was the spindles for the cogs being far too small, a few cogs broke at the spindle as soon as force was applied. I think the cogs were put under extra stress because I didn't align the axes of the spindles on one plane.

Another problem was the smallest cog, the spokes were too small and the height of the teeth were too narrow. This reduced the effectiveness of the teeth. The material itself also became a problem in that the finish of the surface was a little rough on the teeth which created alot of friction and jammed the rotation.

I experimented with running cogs on a 90 degree angle which didn't seem to work at all, whether this was a problem with the rough teeth or the flexibility of the plastic stopping the extra gear from rotating I'm not sure. I noticed that all of the gears flexed a bit so it would be interesting to create them in a more rigid material to see if it is the limitations of the material stopping it from rotating properly.

After reading about a method of smoothing out the surface of printed objects I may find they function more smoothly together. It could also be that I have placed the cogs too close to one another and the teeth are meshing together too much.

The second lot of gears I  made a few alterations. For a start I increased the width of the spindles to make them stronger. Then I increased the thickness of the smaller cogs and made them solid to improve their strength. I also added a bevel to all of the teeth of the three sizes of cogs to improve the smoothness of the meshing of the teeth.

Printing out the block that held the cogs presented its own problems. The first attempt suffered a little warping at one end but still managed to come out square on top, the second block seemed to warp quite a bit  more on the bottom. While the block come out square on top, the warping meant that the spindle of the large cog couldn't fit all the way into the hole meaning it didn't align with the other cogs. This will be easy to fix by drilling through that section and this gave me a better idea to be able to test cogs.

I will take a block of wood and drill holes into it which will enable me to try many different combinations and also see how the gears interact between planes. This will also save alot of time and material, printing the blocks takes an hour for each block and uses three to four grams of plastic per print.

The next step i would like to take will be to design a small functional machine like a wind up car. I will use wood for the body to experiment then once I have the configuration I will make a model to print out.

3D printer maintenance and repair

Hi there, today I will talk about what I have learnt from helping to fix the class printer which had become clogged from its nozzle to inside the extruder head. We began by removing the printer block which contains the extruder, the heating element, a fan and the nozzle.

The printer block is connected to the machine by a magnet and there is a ribbon that plugs into it which unclips easily. To access the extruder cog there is a number of small bolts which are removed using an allen key. Removing the nozzle from the block requires a small socket wrench which comes with the machine.

After trying to remove the nozzle and unclog it, we realised that it is much easier to do so when the block has been brought up to printing temperature which is 260 degrees Celsius. Once up to temperature we unscrewed the nozzle and ran a special piece of wire that has a rough surface inside it to clean it out. We also used a drill bit to clean out the extruder which worked quite well because turning the bit inside the head caught all the softened plastic and bought it out in one go.

How it became clogged in the first place is unknown, it may be the type of plastic or it may have been a breakage with the cord causing it to harden inside the block. What we have learnt from this is to stop trying to extrude it once there is a problem because it can cause the cord to start to clog the whole block once the nozzle has become blocked.

Gears and constraints

Hello there, I have been looking into gears and how they relate to one another. After a few goes I have created a working set of three different size cogs. I then did a tutorial on rotation and transformation constraints that I found on youtube. Here is the link.

http://www.youtube.com/watch?v=j1WNbpX7HPo

What I learnt about making these cogs rotating together is that it's pretty simple to link a larger gear to a smaller one by using a rotation constraint and dialling back the influence of the smaller cog. This is where the number of teeth is important, to make gears run smoothly together they need to be in uniform ratios, I used a 50% ratio.

To make a smaller gear run off a larger one, you need to use a transformation constraint because the rotation constraint doesn't allow a rotation influence of more than one. The transformation constraint can also be used for location and scale restriction but also rotation. This way you tell the object how much it will rotate during a certain rotation of the target object. This rotation was 360 degrees was for the targets. Making an object rotate on a different plane involved using another feature of the transformation constraint which could tell the constrained object what rotation axis it would use for it's selected rotation. For example telling a cog on the x axis to use the z axis rotation of the target object as is desired rotation.

I had a little trouble with this feature in that it seemingly would only work for me one way and caused me to change my main cog to a y axis cog rather than the original z axis rotating cog. Here is how it turned out, I'm happy with how the gears mesh together, hopefully they will work in real life when I print them out.

Gears - Learning to build

Hello there, I did a quick tutorial on how to model gears in blender. It was pretty easy, the next step is learning to give them relational functionality. I found a good tutorial on how to add constraints and make the rotate together as well as defining ratios. That will be the next step. Here is the link for the gear build tutorial.

http://glupor.blogspot.com.au/2012/06/blender-tutorial-1-making-cogs.html

Here is an image of the cogs I built.

Here is a little video of the walk cycle I did as a tutorial. This was quite straight forward to learn, it dealt with manipulating a rig into four different positions and inserting a keyframe for each one in the timeline. By pressing the I key the position of the selected parts become a key frame and will always move to that position at that time. It is a good idea to have everything selected on your model when making a keyframe for an organic object because other parts may move slightly as well.

The other part of the tutorial was making the model walk along a path rather than walking in place. by going into the NLA editor I was able to combine both the motions of walking and moving on a path to make the model walk along. This makes life easier, by being able to loop the walk cycle and just move it around it saves alot of time that would be spent making keyframes. The graph editor was able to change the velocity of movement to a constant rate by making it a vector line after pressing the key V.

Using the Skin Modifier

Hello there, I have done a tutorial which focused on using the Skin Modifier. This seems like a really helpful tool to create figures with amateurs that then can be sculpted into the final shape.

Here is the link for the tutorial.

http://www.blendtuts.com/skin_modifier_04_09_2012

This modifier creates a mesh over a stick figure design enabling you to create complex shapes without having to physically place every vertices. The features of the Skin Modifier include the option to mark loose which means that the veritices selected don't affect topography of the mesh. This is what I did for the collar and hip vertices. Another option is to  mark root. This option defines where the mesh radiates from as well as the spot where the armature will be generated. Equalise radi is an option which smooths out the mesh around the branches of your framework.

A really handy part of this modifier is the create armature feature. This takes the framework of your object and turns it into bones that are already connected and parented. Once you apply the modifier the mesh will respond to any movements in the frame accordingly in pose mode.

As you can see, I took a screen shot with the armature visible to help illustrate the relationship between mesh and frame. It's pretty rough but the purpose of this tutorial was to come to grips with this modifier. The next step would be to use the sculpt tool to create your finished model.

As part of this tutorial I used the Mulitresolution Modifier which smoothed out the mesh alot like the Subdivision Modifier except it allows you to manipulate subdivided vertices when sculpting.

Nut and bolt tutorial part 2

This tutorial took me to new places on Blender, namely the node edit mode. There are a ridiculous amount of options to choose from in there. I think the challenge is using the right one to get the effect you want. I also learnt how to easily make metallic textures using only a texture mode in the options when making a new texture.

Making the bolt itself was straightforward, the tutorial focused on texturing, lighting and effects. The main lesson I will take away is how to use those nodes to manipulate the balance and texture of an object. This is the link below.

http://www.blendtuts.com/nut_bolt_part2