SteveCox3D

Agree on the use of Fusion 360 for modelling threads that have to be 3D printed, I use that all the time. Some of the problem with threads comes from the fact that the outside thread will tend to be 3D printed slightly larger than the nominal size, and the inside thread will be slightly smaller than the nominal. The result is in an interference fit rather than the running clearance required for a thread. I usually engage the two threads together and then work them against each other and gradually they bed-in and work as they should. It can be useful to introduce a lubricant to make this easier (as long as you use a lubricant doesn't affect the material).

I think getting to talk to the Materials team would be good as I think this is the most fascinating area of development for me. Understanding what testing programme they go through for new materials in more detail would be great for the community to understand.

Glad it worked out! This forum is all about helping each other, so it's great to get your feedback that this solved your problem.

The above contributions to this thread by @geert_2 @laverda and @JohnInOttawa all make great points, especially in relation to the load cases that might be seen by this part either in normal, or even abnormal, use. The part in this case study was produced from a Generative Design set-up using three different load cases acting on the pivot of the part. None of those three load cases were applying a lateral load to the pivot because it was considered that the connecting part is constrained in such a way that it cannot transmit any lateral load, so the design synthesis has not had to take that into account. One of the key things to realise about Generative Design is that it changes the role of the engineer/designer at the very start of the process. We are used to getting quickly into designing solutions for the part we need, but GD makes us think much more about the problem we are trying to solve. That means spending more time at the beginning thinking through all of the possible loads, and directions of those loads, that the part will see during it's lifecycle. That in itself can be a challenge because sometimes we don't know all of that information, which is why we tend to over-engineer parts, as John pointed out. To address that I've seen Generative Design being used in conjunction with load data that's been generated from real time, physical testing. For instance instrumenting a car suspension set-up and then testing it to the absolute limits on a test track will give much more load data that can be input into the process. That should generate a more robust solution. GD is something that will make us think in a different way, and more deeply, about the things we design in order to fully take advantage of it's opportunities. It's still very new and it's great to have discussions like this as we start to explore the way that we use it.

@cloakfiend It's interesting to see in this case that the optimised part, which had much thinner sections, had a much better burn out of the PLA than the original baseline part. So it seems like the shapes can be fairly complex, with thin walls and sections, and still create good quality cast parts

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!

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

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.

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!

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 ………….

@Nicolinux I'll take a look at these and see what would be the best action to take to improve the strength

@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.

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.

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

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 . 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.