SteveCox3D

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.

Merci @darkdvd

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

@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.

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.

@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?

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.