SteveCox3D
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Posts posted by SteveCox3D
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How can the very latest, cutting-edge design software combine with a 5,000 year old manufacturing technique to deliver outstanding weight reduction opportunities?
Designing for light-weight parts is becoming more important, and I’m a firm believer in the need to produce lighter weight, less over-engineered parts for the future. This is for sustainability reasons because we need to be using less raw materials and, in things like transportation, it impacts upon the energy usage of the product during it’s service life. Lighter products mean less fuel to move them around, which can make our fossil fuel reserves go further, or make more efficient use of the renewable energies that we’re now beginning to adopt.
Generative Design (GD) is the very latest design software released by Autodesk and is now included in Fusion 360, which is at the heart of their "Future of Making Things" strategy for Design and Manufacturing. It changes the way we design things and can deliver very efficient designs that deliver structural performance with optimised use of material.
The aerospace industry is expected to be one of the early adopters of this technology because in that industry the cost and environmental savings from improved fuel efficiency carry the greatest rewards. Also, I see interest from the automotive industry for the same fuel efficiency reasons, but in the long term the drive for lighter weight parts could benefit many industries, even those outside of transportation. Another example of the benefits of lighter weight alongside reduced material usage is that shipping costs for parts reduce as their weight reduces, which can therefore also deliver cost efficiencies.
GD is targeted initially at metal parts where the biggest opportunity for light-weighting exists. The complex forms it generates though often means that parts conceived in this way cannot be made with conventional manufacturing routes. They therefore need to use Additive Manufacturing (AM) techniques to produce them.
The route of using high energy, laser-based AM to do this comes with associated high costs because of the specialised set-up knowledge required together with expensive processing, and post processing, to deliver a quality-assured part. This project explores the possibility of a more cost-effective route to a metal GD part which, even though at this stage may be just used for a small quantity of evaluation prototypes, can act as an enabler for understanding the potential that GD has to offer.
This is the baseline design for this project. It is an aluminium bracket design similar to those used in aerospace applications to mount control surfaces, and in this form has not been optimised for weight. This design would weigh 383 grams in the intended material, aluminium A356.
After processing this through Generative Design in Fusion 360 it’s time to review and evaluate the many alternative design options presented and decide upon the design that is considered the most appropriate taking into the other factors that have an influence on design selection such as manufacturability, aesthetics etc.
This was the design option chosen for this part and Fusion 360 was used to create the final version of the model.
The bio-mimicry that’s evident in most of the designs created by GD is interesting to see, in this case the design of the part can be seen as essentially a swept I-beam (which engineers, especially those in construction, are taught is a strong section), but with tendon-like attachments back to the mounting points to carry the tensile loading that’s created by the applied loading conditions
What GD does is to turn the standard design workflow that we’re familiar with on it’s head. Traditionally we design a part and then stress test it virtually to determine if it fulfils the required structural performance. Any failures seen during this process require an iterative loop back to the design to correct them.
With GD the stress analysis is a core part of the design synthesis, and happens as the part design iterates, which means that the output at the end should meet the requirements of the intended loading requirements. The software is searching for an optimal solution where the stress is ideally evenly distributed across the part as can be seen above.
To prove that everything is good with the finalised design this part has then been virtually tested again in Fusion 360 to confirm that the original loading requirements are still met
So we've created our lightweight part design, and maybe now we need to produce that in aluminium A356 to do some physical testing, but don’t want the expense of using a metal AM process. What follows is a way of achieving this where FDM 3D printing can play a role as an “enabler” to help create the final parts in conjunction with a very old (if not ancient) manufacturing technique called investment casting. This technique is 5,000 years old according to Wikipedia.
The company involved with casting this project is Sylatech who have been using Ultimaker 3D printers as part of their process for investment casting of prototype parts
Sylatech took the .stl file of this model and used it to create a 3D print of the part on an Ultimaker 3 in PLA. This PLA part was then used as the pattern in the investment casting process where it is submerged in plaster under vacuum conditions to ensure that all air is excluded from the mould and creates an accurate reproduction of the surfaces of the part. The picture below shows a display box which demonstrates the set up of the 3D printed parts partially encased in plaster.
Once the plaster has hardened the casting box is put into a furnace at very high temperature in order to burn out the PLA, leaving behind a cavity into which molten aluminium can be cast.
After solidification of the metal, and cooling of the mould, the plaster is broken away from the parts, and then they can be quickly and easily removed from the material feed gate resulting in these aluminium A356 versions of the PLA original.
The final part weighs 122 grams which is a weight saving of 68% over the original baseline part, which shows the potential that GD has to make significant reductions in weight and material usage. Using this method we now we have an excellent quality physical part made very quickly in the final intended material in order to commence some physical testing.This is a different route to get to that physical test part in metal at a fraction of the cost of having it metal additively manufactured.
It also shows how a brand new, cutting edge piece of software that only became available in May 2018 can combine with FDM 3D printing (which many people still see as a new technology even though it’s been around for over 20 years) and a 5,000 year old manufacturing technique to deliver potentially huge benefits in weight and material usage.
Using the investment casting route in this case study is why I chose the title for this article, and shows that we can effectively go “Back To (Deliver) The Future”.
Do you see the need for lighter weight parts in what you do, and can you see the potential benefits of using Generative Design and this method of producing metal parts?
I'd welcome comments, suggestions, and discussion about any aspects of the above article, the next steps that I'm looking at are how this process could scale up to batch production of the parts using 3D printing techniques that could support low volume production quantities
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In the past I too have got to a position where prints no longer stick properly to what seems like perfectly clean glass. It's as if there's something invisible to the naked eye that's causing a lack of adhesion.
I found that using one of those scouring creams like you use for cleaning limescale off in the bathroom (Cif, it's called in the UK) seemed to rejuvenate the adhesion. These creams have a mild abrasion effect and whilst they're not aggressive enough to affect the glass in terms of creating any scratching, using this seems to "rejuvenate" the glass plate so that prints then stick like they did before.I have no idea what it's doing, either it's removing an invisible film that's built up over time, or having some other effect on the glass to address whatever's caused the deterioration - what I do know is that it works for me.
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Thanks for the comments @geert_2
The interesting thing about the pliers is that the service life could be long because there are no moving parts and the flexible part is working well within it's elastic limit so it's response should remain constant. I'm used to testing things to determine their service life and this feels like it would cope with a very high number of operating cycles.
The clamp force isn't enough to do a mechanical job like tightening a nut, but it does have a soft pinch force like you can get with your fingers. Someone who I showed it to was very interested in it as a potential application where they were trying to automate strawberry picking which needs a damage-free grip. So-called "soft robotics" is a new area where robots become less mechanical but have more of a human touch and maybe this would be appropriate for that.
I did try some alternative lattice shapes, but this very regular pattern seemed to work best. It's something that I probably need to return to and see what changes I could make. Simulation of this is quite difficult because it's a non-linear material behaviour, so trial and error 3D printing different patterns is probably the best option to develop the idea further. At least 3D printing makes that easier to do!
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In my previous post on DfAM (Design for Additive Manufacture) I concentrated on how to deal with some of the design principles needed to ensure the manufacturability of a part using Additive Manufacturing (AM), or 3D Printing (3DP).
In this post I’m going to concentrate on the way DfAM can take advantage of some of the unique capabilities that AM and 3DP has to offer. There are a number of different advantages available and we’ll look at each one in turn…………
“Complexity Comes For Free…..”
This is a statement that’s often made about AM/3DP. It’s not always completely true because dealing with complexity in this method of manufacturing can incur longer manufacturing times and sometimes, as the saying goes, “time is money”. However it's true that designs for this type of manufacturing method can be considerably more complex, yet still be feasible to make, compared with those designed for the more traditional methods of subtractive manufacturing, forming, or casting.
One great example of design complexity is this Digital Sundial designed by Mojoptix :
In itself this is a very clever piece of design that uses mathematical formula to generate the geometry which creates a digital time image from shadows cast by the sun. However, that geometry in some areas is so complex, with many thin internal walls, that the only feasible way of making this is using AM/3DP.
In other applications this design freedom helps to realise complex cooling channels inside parts where efficient heat exchange is one of the key performance requirements. Channels can be provided deep inside parts where they are most effective, as opposed to being provided only where they can be manufactured. The result is that optimal functionality can be the focus for the part design rather than how it can be manufactured using traditional methods.
The ability to make thin complex structures that are often “locked” inside parts is one of the aspects that is allowing the use of complex lattice structures for light-weighting of parts made using 3DP/AM. These internal lattices are similar to the internal structures that using infill in Cura produces, however the advantage of these more advanced lattices are that they can be created from understanding the stress analysis of the part as a solid structure. The lattices created can then be very dense in high stress areas and much less dense in lower stress areas, resulting in significant weight savings.
Here’s an example of such a variable structure in a cut-away section of an advanced concept that I worked on for a marine pilot ladder
I personally think that the use of AM/3DP for light-weighting is one of it’s most exciting possibilities and one that could play a key part in sustainability of design and manufacturing in the future.
At the moment AM/3DP is being used for reducing weight in high value/low volume applications such as aerospace, but it the future I expect it to also provide this advantage in higher volume/medium value applications such as automotive.
Light-weighting using AM/3DP is a subject that I’d like to return to in more depth in a future post.
Multi-Material Prints
With dual extrusion 3D printers such as the Ultimaker 3 and new Ultimaker S5 it’s possible to combine two quite dissimilar materials on a single layer. That gives the opportunity to create some interesting concepts that can be produced in a single 3D print.
One example is this pair of pliers that I designed specifically as a dual material print. The main structural parts are in a rigid material (in this case PLA) and the central latticed core, which behaves like a pivot, is made from a very flexible TPE (thermoplastic elastomer).
In order to get a good bond between the two materials I didn’t want to rely on material adhesion alone because of the shear forces acting across the joints between the two materials as they are operated. So in this design I incorporated interlocked mechanical connections between the two materials where those features were printed through the layers. This in itself was another example of DfAM, because understanding how the layers would be printed allowed me to design a robust, yet manufacturable, connection between the two dissimilar materials.
In the future we will probably see 3D print heads that go beyond two materials to multiple materials, which will open up further new opportunities
Part Consolidation
Another opportunity using DfAM is to design what would be a multi-piece component to be manufactured in a single pass. This is called part consolidation and it reduces assembly time, and can also provide fully assembled parts that would be impossible to achieve through normal methods.
The advantage of these are reduced inventory, reduced weight, elimination of assembly time and some design freedom, but they can sometimes have the downside of reduced levels of serviceability, so that needs to be a consideration.
A good example of part consolidation is the antenna bracket below that was created by Airbus for the Eurostar E3000 communications satellite. This was previously a four part assembly with many internal fixings for assembly of the fabricated parts which was replaced with an AM single piece design, which also had the benefit of being both stiffer and lighter than the multi-part assembly it replaced.
See this TCT Magazine article for full details
Integrated Mechanisms
Another opportunity that Part Consolidation can provide is the possibility to create integrated mechanisms that are multi-part assemblies with functional mechanisms that work straight off the printer.
Perhaps one of the most famous is the NASA Space Wrench that was 3D printed on the International Space Station as part of their 3D Printing in Space investigations for supporting long-term exploration missions.
In a weight-less environment it’s probably not a good idea to have lots of small parts floating around, so this was designed as a working wrench where the ratchet mechanism was created directly inside the part during printing. The first time the wrench is operated any small bonds between the parts are broken and the ratchet mechanism works.
Another good example of an integrated mechanism is this Platform Jack that can be downloaded from Thingiverse
Part Customisation
Another key advantage of AM/3DP is it’s ability to take advantage of part customisation where every part made differs slightly to suit individual customer needs. Here DfAM plays a role in the area of Mass Customisation where a mass produced part is used with a customised 3DP/AM part to produce something that has the best of both worlds.
Mass Customisation earbuds are a good example of this where mass-produced earphone drivers come together with 3D printed tips that have been created from a scan of your particular ear contours.
This leads into the ability to satisfy something called “The Market-of-One”. This opportunity is where either mass personalisation, or a fully customised part, is a true one-off product that will perhaps never be repeated, but for which a commercial opportunity exists.
In DfAM this customisation can be achieved by using a full parametric design approach where the key adjustable features in a design are defined in a parameter table such as this example below in Fusion 360 :
This table allows new dimensions to be quickly input into the parameter table and the design then updates automatically to reflect these without the need for any additional design work. The customised design can then be rapidly output to slicing software for final preparation. In this way customised designs can be produced and prepared for manufacture in a matter of minutes.
Have You Taken Advantage of DfAM ?
The difference between what’s covered in this post compared with DfAM in my first post on the subject is that all of the above techniques need to be considered at the concept stage of designing. In this case it needs the AM/3DP mindset to be adopted right at the very outset. There's an example of that in this video made by HP which shows some of the above DfAM principles I've described combined into a very durable 3D printed part with a high service life
It can be quite a difficult transition to make to take advantage of the freedoms that AM/3DP offer, and it maybe needs a degree of innovation and creative thinking to make the most of the opportunity. One of the things that is now starting to emerge are higher education courses and apprenticeships dedicated to the use of AM/3DP, and these will undoubtedly be useful in embedding these opportunities in the design-make workflow for the workforce of the future.
At the current stage of DfAM we have merely scratched the surface of what we can do and I’m really excited to see how we exploit the advantages I’ve outlined above in the future. So, I’d be really interested to see and hear from the community how you’ve taken advantage of DfAM, and what your aim was ………….
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@Nicolinux I'll take a look at these and see what would be the best action to take to improve the strength
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@JCD Interesting to see your theory about warping. In this case it's the stresses that are locked into the part caused by the thermal effect of heating up a material and then quite rapidly cooling it that induce the warping.
Warping is a very significant issue in metal 3D printing where the energies are much higher than in FDM. It's why you see metal prints with what look like support structures, but are in fact structures to anchor the print to the buildplate to prevent that warping from occurring.
Even when those structures do their job and stop warping there can be huge internal stresses locked into the part which is why metal prints often need to be stress-relieved by heating them up to a high temperature and then cooling it at a much more controlled rate to deal with that issue.
As you mention, making the internal corners stronger would be a way of resisting the warping forces in an FDM print.
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Hi @Nicolinux Fusion 360 could do the analysis, but the infill patterns would need to be modelled in Fusion which would take a little time to do, especially for the more complex 3D infill patterns. The stress analysis would also be a little more complex because of the greater number of surfaces that need to be meshed to support the analysis. If Fusion 360 wasn't able to handle that locally then it could be handed off to the cloud.
Do you have a particular part in mind that I could take a look at because it's a very interesting question.
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I don't want anything, so disable this feature. But, I agree with other comments here that a suffix is better than a prefix as a prefix makes it harder to spot the file name that you're looking for on the small screen on the UM2+ and UM3
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Regarding the @SandervG and @geert_2 discussion on DfAM's role in aesthetic / high surface quality output, here's my take on it.
For me, whilst DfAM does have some bearing on aesthetics and surface appearance, my own view is that it's much more related to the file preparation, printer settings and post-processing area of 3DP. It can't be completely disassociated from the design process because creating good consistent smooth surfaces at that stage is definitely needed for good aesthetics. The best model I have looks great in whatever material you print it in, and that's because the digital model is so good, so detailed and so well designed
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But, for me, I generally think about aesthetics when I have the .stl model, because I often have to make a high quality job of printing other people's designs. Optimising the 3D print quality to create a good aesthetic then tends to then involve combining Meshmixer, the Cura set-up and material considerations.So, for this thread, I would be in favour of keeping it as a discussion for DfAM for achieving the necessary functional performance.
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Thanks @gr5 !
The tangential nature of a fillet generates the long step on the first layer that isn't that effective because the next layer steps a long way back from it so you don't really get the benefit. Using a chamfer adds the structure more uniformly.
I agree that probably a kind of parabolic shape could be even more optimum, but CAD software is set up to put in fillets and chamfers in a single operation on corners whereas using a non-uniform shape is a much more involved workflow. -
@geert_2 Thanks for contributing to the discussion. Indeed, DfAM is influenced by many factors, and what your intended use for the 3D printed part is. So this is quite a large subject and my original post is there to encourage debate and other people's perspectives and techniques for DfAM.
Many of the things that you mention I also do in my 3D printing work. One technique I use often is to split a print and make it in several parts which can be glued together rather than have to use support material. I do tend to be a little obsessed by quality and on a single extruder machine I would rather find ways of printing without support to get the best surface finish without extensive post-processing.
You also make a good point that the quality of the layer "weld lines" is very dependent on the printer settings and have a big influence on how the layers fuse together
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@Brulti That's a really good point and something I think we will see more of in the future. For instance in Fusion 360 there is a dedicated CAM environment where you can carry out your machining set-up, and in the longer term I expect to see a similar environment for 3D printing being added, maybe based upon Autodesk's Netfabb software.
It's important, as you say, to catch the manufacturing problems at the design stage when it's easiest to do something about them.
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I'm Steve Cox, a member of the Utimaker Community. I'm an experienced engineer having spent many years in the automotive industry but I'm now focussed on the world of 3D technologies, specifically 3D product design and 3DPprinting. I'm an Autodesk Certified Instructor for Fusion 360, so many of the images in this post are taken from that design software but this post is not specific to that software but is about designing for 3D Printing and Additive Manufacturing. This is a first of a series of blog posts in this area that will be focussing on how engineering is interacting with the latest 3D technologies.
Additive Manufacturing (AM) and 3D Printing (3DP) - whilst the way they produce an object from nowhere can often seem like modern-day magic, the truth is that in many ways they are no different to any other way of making things.
Every method that we use to manufacture things has it’s own rules that we need to consider when designing. These rules are known as DFM – Design For Manufacture.
This approach takes into account the pros and cons of the chosen manufacturing method to produce a design that can be made repeatably, reliably and to meet the intended function and life expectancy of the product.
This way of thinking when applied to AM (or 3DP) is now becoming known as DfAM, or Design for Additive Manufacture.
In reality there are two aspects of DfAM, the first we will deal with in this post where we will concentrate on the use of DfAM applied to detail features of the design to ensure manufacturability. The second aspect is using DfAM at the conceptual design to realise some of the unique capabilities that AM has to offer, and that will be covered in a later article.
The rules of DfAM tend to be slightly different for each type of AM/3DP technology. Here we will be assuming that we are using Fused Deposition Modelling (FDM) 3DP but, for instance, in metal AM residual stresses build up in the part during manufacturing due to the high local energies applied by the laser or electron beam. These have to be taken into consideration if warping and possible early-life failure are to be avoided. So, in metal AM, the use of DfAM can involve designing out thick sections where heat build-up can be greatest. This is seldom a significant issue in FDM 3D printing.
Two of the main DfAM considerations in FDM 3D printing are layer orientation and overhangs which we will take a closer look at here.
Layer orientation
When a detail design is being prepared for manufacture one of the first things to consider is the loads that will be applied to it, and 3D printing is no different. There can be potential weaknesses in 3D prints in the “welded” joints that exist between every layer which provide multiple potential crack propagation opportunities.
So at the detail design stage the loading direction may need to be taken into account, which can in turn lead to a decision being made on the print direction to be used very early on and that will then set the tone for the rest of the design.
In this particular case the stress analysis in Fusion 360 on a loaded side wall of a design shows that the peak stress occurs on the inside face of that wall near to it’s base which, if we were to print it in this orientation, will coincide with the end of a layer and hence one of these potential crack propagation sites :
Which can lead to this :
The better way of 3D printing this design to withstand this loading condition would be to orientate the printing direction by 90 degrees to ensure that the load is being applied along the layer lines rather than across them.
The strength of a part with this layer orientation will be many times greater under the loading condition described previously, though the amount is difficult to objectively state since simulation software taking into account the layer construction of AM is still an emerging area of activity.
So this is a DfAM consideration to think about at the very start of your design - what are the main load bearing directions and is it possible to optimise the design to ensure that the way that you will make the part which does not result in loads being applied across a layer?
This is the single most effective step that you can take, but it may not always be possible to do that, in which case you need to employ mitigation factors into your design.
The usual best practice in any design is, where possible, to add a fillet (or radius) at the base of the wall to counteract these high stresses. This reduces the local stress moves the higher stress point further up the side wall and is an optimal way of adding strength with the addition of minimal material.
However, in AM/3DP it is often a better option to use an angled face rather than a curved face to achieve the same effect
The reason for this different approach is that the "staircase" of layers in more uniform in the case of the angled face, whilst with a fillet radius the smooth blend into the base results in a longer first layer step which reduces it's effectiveness.
So this is another aspect of DfAM where strategies used for other methods of manufacture may need to be subtly modified to make them most effective when using this particular method
Overhangs
Once the print direction has been selected then the design of overhangs, and preferably the elimination of as many of these as possible, can be addressed. Fewer overhangs means less requirement for support which leads to a more efficient print time, lower material usage and reduced post processing time for removal of supports
This is the most obvious way to eliminate an overhanging feature :
Things like this are simplistic and often easy to spot, but you may find that your design is more complex than this and there is a tendency to design from experience with traditional manufacturing methods and put in features that aren’t good for AM almost without thinking.
For instance in this example of a flanged coupling the features with blind tapped holes for the connection have been designed with a feature that would cause no problem for a moulding process but produce an overhanging area for 3D printing (highlighted in red when viewed in Cura)
With some re-examination it was possible to re-imagine these features like this which result in no overhang and hence no support.
Rather than fill this post with lots of examples of individual examples of this kind of comparison my recommendation when engaging with DfAM is to regularly check your design in the slicing software as your design develops, looking for those overhanging areas using an inspection tool that highlights those areas, or looking through the layer stack for areas that look difficult to print. The layer stack should be something that’s looked at before every print as a matter of course and is also a great way of spotting issues at the design stage that you may be easily able to address.
In Fusion 360 the ability to go from the design workspace to the slicer software (such as Cura) to check for printability can be done with a single click of a button, and without the need for any time-consuming exporting and subsequent importing of .stl files. This can make the iterative process of Design → Check → Modify → Recheck much quicker, and result in a faster convergence to an efficient design for additive manufacture
The approaches we have looked at here are when DfAM is applied at the detail design stage and looks to address, and deal with, the drawbacks of 3DP/AM.
In a future post we will look at applying DfAM at the conceptual design stage where the advantages that AM has to offer can really become very valuable.
This approach can be much more powerful and result in designs that really do provide unique and extremely effective solutions that would have been unthinkable just a few years ago.
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@steveh Have the design guys given you any adjustment in the glass doors of the S5 during assembly? Having those doors in good alignment with even gaps will give out the right premium quality message on this printer and, as a part that you've never had to deal with before, are there any other things you've had to do to take into account for handling these parts at the plant?
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Some prime tower improvements have been incorporated into the latest Cura 3.3.1 release. Prime towers are now circular rather than square which should give them more strength and rigidity, plus better buildplate adhesion. Previously prime towers often broke by a "hinging" action across one of the layer lines on the straight edges of the tower, that hinging point doesn't exist now with a circular-shaped tower.
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I'm the same as Didier, I have printed with this filament and used the recommended colorFabb settings without any real problems. My main issue was ensuring that the material didn't warp on the buildplate, so I had to make sure I had a good, even adhesive layer on the glass before printing with it.
An example of the parts that I printed with it are attached.
If you suspect it could be due to the oiliness of the material then make sure first that the knurled drive wheel in the feeder is clean and free from any clogging, and maybe also play with increasing the pressure of this wheel onto the filament using the adjuster screw on the feeder.
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Fusion 360 generally handles the generation of .stl's very well.
I have created hundreds of models from Fusion 360 designs without any issue, so I would not think that Fusion 360 is at fault. When you export out an .stl in Fusion you have the ability to choose the refinement level - Low, Medium, High or Custom. Low refinement can give a facetted result which may link into what you said on your original post about the printer drawing small triangles rather than long smooth lines.
Always start with the High setting, Low is generally only useful if you file sizes become huge because of the number of triangles it creates. In your example High should work fine.
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@gr5. - There's a slight contradiction in what you say in your last post.
You correctly stated earlier that .stl files are unitless, so you can't actually tell your CAD programme to save the stl file in mm or inches. You should model in whatever units suits your design needs, the fault then lies with this unitless format that stl files get saved in. It's only when you import into the slicing software that the unit length of say '2.5' in your .stl becomes either 2.5mm in a slicer that uses metric, or 2.5" if it's a slicer that uses imperial.
It does work the other way round - if I import an .stl file into Autodesk Fusion 360 it asks me before displaying it what units I want to use so that it knows what units to apply to file to determine the size.
All of this should get fixed when .3mf becomes the de facto file format standard for 3DP/AM, as this will take away this potential error point by carrying the units that it was originally designed and saved in (it might take a long time before we get to that point though!)
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For whatever reason the wall thicknesses of this model are too thin for a 0.4mm nozzle to print. You can see this if you switch from the solid view to the layers view. If I switch to a 0.25mm nozzle in Cura 15.04 I can then see that all of the walls are being printed.
The problem lies not with Cura, or the printer, but the original design. Either the wall thicknesses were not made thick enough in the original design, or the way the part has been modelled is as a collection of surfaces rather than a solid model, and some of those surfaces are not connected to produce a solid model.
I looked at this in Meshmixer and there were a couple of minor defects that it has repaired, but in Cura the surfaces will only print with a 0.25mm nozzle setting. So I suspect this is a problem with the wall thickness of the model
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Thanks @yellowshark
I've just printed in this material my first design that was created by Autodesk's Generative Design programme, which is the first genuine piece of "Computer Aided Design" software.
It's come out really well, picture to follow..............
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Not sure what the age/grade of the students is, but this is a great introduction video that shows how 3D printing/additive manufacturing compares to the other ways of making things, and what it's possibilities are.
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I've been printing with colorFabb's new PA-CF Low Warp material recently to understand it's potential for strong, end-use parts, and to understand the settings required to get the best result. These two prints are produced using it, the lever is a direct copy of one of the "showcase" prints used by MarkForged to show what their printers are capable of (I believe it's a Ducati brake lever) which I produced so that I could compare a UM-produced "composite" print vs the MarkForged version.
The connecting pipe is my own design with a few elements of Design for Additive Manufacturing (DfAM) added in to eliminate any overhangs, and hence need for support.
Both parts were printed at 0.15mm layer height, using a 0.4mm Olsson Ruby nozzle on a UM2+ at 260 degC, which is at the limit of the hot end on this machine but is at the bottom end of the recommended print temperature window of 260-280deg C. For that reason I ran at 75% of my normal print speed to keep the temperature maintained, together with a 35% fan speed and 105% material flow setting. My first attempts with this material had issues with interlayer adhesion, these settings appear to have fixed that.
The material is supposed to print on a cold bed, but I have found that using a 40deg C bed temperature works well (after spending working for 4 years 3D printing with a heated bed suddenly printing with it turned it off seems hard to come to terms with!). The material lives up to it's name because even over a 6 hour print there is no warping evident, and the material prints without any hissing, popping or spitting that you often get with PA/Nylon materials - the material has only been stored in a sealed bag with dessicant since I first opened it around five weeks ago - no drybox has been used.
I'm really pleased with the results, both parts are very, very strong and I chose to use multiple shells (20 on the lever and 10 on the pipe) rather than use an infill, which seems to have been successful. The appearance of the pipe is especially good, the black matt surface really does disguise the layer lines, and gives the part a more "moulded" rather than 3D printed look to it.
So how did the lever compare to the MarkForged? The MF part was exceptionally stiff and did have an advantage over this part in that respect, but then how often do you really need something with that kind of ultimate stiffness? I have to say that the MarkForged printers are very well made, easy to use and produce exceptional parts, but they do have a narrow area of focus and specialism. These latest prints have bought it home to me how versatile a UM printer can be - it can be producing artistic prints one day, and the next exceptionally strong, engineering-grade, end-use parts.
Big respect to Ultimaker printers for their ability to cope with so many different materials and print reliably using them, and to companies like colorFabb for producing some exceptional filaments to keep on extending their capabilities even further!
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2 hours ago, cloakfiend said:
now some photos of it polished...lol I went a bit overboard on the photos, but I have some interesting results...
Thats it for this one, moving on to the next...
Beautiful work @cloakfiend !!!
"Back To The Future" using Generative Design & Investment Casting
in Industries
Posted · Edited by SteveCox3D
Many thanks @JohnInOttawa for contributing to this discussion and the points you make are absolutely valid to this new way of designing.
Firstly Generative Design creates surfaces that we would not ordinarily design ourselves, but when those surfaces are derived from the results of stress analysis it's fascinating to recognise the echoes of the way nature designs. Maybe nature is the greatest designer of all, because it has evolved to make the most effective use of the materials around it.
What you've also outlined is something I'm working on at the moment in terms of aiding people to understand the potential pitfalls of Generative Design. One of those is deploying Robustness & Reliability Engineering methodologies to ensure that the part can perform not just it's "Ideal Function" but also be resilient to the "Noise Factors" that components and assemblies are subjected to. These can be things such as the abuse loading, and environmental factors as you mention.
I'm about to write a presentation that raises the awareness of this. One example I intend to use is that Generative Design will design you a very lightweight chair based upon four contact areas to the ground and a specified seating load. That will work under normal circumstances, but we all have a habit of rocking back sometimes onto two legs of a chair, and doing that that might take the design into an unsafe area because that load case was never considered in the original set up.
We're at the start of our journey with these new design techniques, and there's still lots to learn - but it's going to be an exciting ride!