Posted on

Italian Researchers: Eliminating FDM Support Structures with New Algorithm

As researchers from Italy present a novel system for avoiding the use of support structures in additive manufacturing processes, they delve further into an issue that continues to plague users who would prefer not to spend the additional time in post-processing efforts. With their findings outlined in ‘Fused-Deposition-Material 3D-Printing Procedure and Algorithm Avoiding Use of Any Supports,’ the authors explained that they performed their study with FDM (FFF, Material Extrusion), but their work could be transferred to other methods of 3D printing too.

In this study, the research team recognizes the benefits of 3D printing, from lower costs, lower production times, less waste, less space needed for inventory, and more, but they emphasize the desire to truly move away from subtractive manufacturing in using only what material is needed—without any requirements to remove supports later.

“Considering the high number of printable materials and structures that can be realized, together with the peculiarities of FDM technology, it is possible to achieve various and interesting physical proprieties, such as flexibility, toughness, thermal resistance, and electrical conductivity,” state the authors, going on to point that that logically, printing without supports is highly desirable to refine quality, as well as conserving materials.

(a) Support-based object and (b) support-free object.

One of the best ways to avoid dealing with bridges and overhangs (areas that initially lack support during the 3D printing process) is to ‘design for printability.’ This may not always be possible though; in fact, the researchers point out that can often be nearly impossible when designing parts and prototypes.

There are other options also for avoiding having to 3D print with support structures, such as designing parts into a variety of sub-blocks which are easier to deal with in fabrication. While the process of removing supports is eliminated though, users must still spend time in post-processing for assembly, finishing, and more.

(a) Object with poor printability; (b) printable object filleting the floating area; (c) printable object splitting critical area from main body.

Although there are a variety of other choices that could be made regarding design, printing, and post-processing and finishing, the researchers created an algorithm for manipulating the slicing process, allowing them to still print ‘supportless bridges and very steep overhangs.’

Flowchart of proposed algorithm.

For this study, the researchers integrated their new method into Tips slicing software—a customized version of Slic3R. For 3D printing, they used a 3DPRN H5, featuring a dual tilting extruder setup.

(a) Testing 3DPRN LAB H5 FDM printer; (b) dual-extrusion setup utilized for test.

Four different samples were created in the study as the researchers created three with a 90° overhang, and one with a bridge. Each sample was 3D printed ten times, alternating with supports, without, and then with the use of the Print on Air algorithm.

Test samples printed for analysis: (a) bridge, (b) rectangular 90° overhang, (c) circular 90° overhang, (d) triangular 90° overhang (pictures not in scale with each other.

“The layer height was set at a constant value of 0.2 mm, while speed, acceleration, jerk, and cooling were automatically set by the slicer,” explained the researchers.

While there was ‘no effective’ measurement available for samples without supports, floating layers were reported as ‘drooped’ and the prints failed.

“PoA, on the other hand, was capable of remaining within one-layer error (0.2 mm) from the ideal dimension. Supposedly, this error came from the cooling deformation of the plastic (wavy-surface finish) rather than actual material droop; hence, a better cooling profile could further improve the results. Moreover, for larger pieces, this issue is inherently reduced since the extruder physically moves farther away from each deposited strand, reducing unwanted heat exchanges between itself and printed sections.”

Ultimately, the researchers decided that the procedure would be best used when overhangs were required, rather than bridges.

Printed samples: (a) bridge structure (left to right): Print on Air (PoA), supports, supportless; (b) rectangular overhang (left to right): PoA, supports, supportless; (c) circular overhang printed with PoA; (c) triangular overhang (left to right): PoA, supportless.

“The proposed approach can be applied to any object, including long bridges and convex surfaces. The algorithm was accurately tested both with differently shaped overhangs and bridges,” concluded the researchers.

“From analysis, we can conclude that, regardless of shape, the supported structures showed the best accuracy across almost all measurements. However, given that, from a geometrical point of view, the accuracy of the obtained shapes with the proposed algorithm was fully comparable with the previous, considering the saved material, time, and postprocessing, our proposal is a valuable tool.”

Dealing with supports and finishing processes will undoubtedly continue to be an ongoing conversation among 3D printing users and those engaged in AM processes as well as integrating innovation into robotics, developing other methods and tools such as cutting devices, soluble supports, and more.

What do you think of this news? Let us know your thoughts! Join the discussion of this and other 3D printing topics at 3DPrintBoard.com.

[Source / Images: ‘Fused-Deposition-Material 3D-Printing Procedure and Algorithm Avoiding Use of Any Supports’]

The post Italian Researchers: Eliminating FDM Support Structures with New Algorithm appeared first on 3DPrint.com | The Voice of 3D Printing / Additive Manufacturing.

Posted on

Researchers Decrease Support Structures for Models Through Multidirectional 3D Printing

An illustration for the idea of the algorithm: (a) a progressively determined planar clipping results for generating the optimized base planes, and (b) the inverse order of clipping planes results in a sequence of regions to be fabricated where the printing direction of each region is the normal of its base plane. The orientation of a printing head is fixed during the procedure of physical fabrication. The parts under fabrication are reoriented to realize the multidirectional 3D printing.

In most planar-layer based 3D printing systems, material collapse is prevented on large overhangs by adding support structures to the bottom. But support structures in single-material 3D printing methods have some major issues, like material waste and the possibility of surface damage. This can be helped by introducing rotation and turning the hardware into a multidirectional system, where models are subdivided into separate regions and each one is 3D printed along a different direction.

L-R: Snowman models fabricated by an FDM 3D printer and the team’s multidirectional 3D printing system by adding only one rotational axis on the same 3D printer.

A team of researchers from Tsinghua University, TU Delft, and the Chinese University of Hong Kong developed two types of multidirectional 3D printing hardware systems: one modified from an off-the-shelf FDM 3D printer with an added rotational degree-of-freedom (DOF), and the other implemented on an industrial robotic arm to simulate a tilting table for two rotational DOFs. They outlined their work in a paper titled “General Support-Effective Decomposition for Multi-Directional 3D Printing.”

The abstract reads, “We present a method to fabricate general models by multi-directional 3D printing systems, in which different regions of a model are printed along different directions. The core of our method is a support-effective volume decomposition algorithm that targets on minimizing the usage of support-structures for the regions with large overhang. Optimal volume decomposition represented by a sequence of clipping planes is determined by a beam-guided searching algorithm according to manufacturing constraints. Different from existing approaches that need manually assemble 3D printed components into a final model, regions decomposed by our algorithm can be automatically fabricated in a collision-free way on a multi-directional 3D printing system. Our approach is general and can be applied to models with loops and handles. For those models that cannot completely eliminate support for large overhang, an algorithm is developed to generate special supporting structures for multi-directional 3D printing. We developed two different hardware systems to physically verify the effectiveness of our method: a Cartesian-motion based system and an angular-motion based system. A variety of 3D models have been successfully fabricated on these systems.”

The researchers wanted to create a 3D printing system that would be able to “add rotational motion into the material accumulation process” to ensure fewer supports, if any. To do so, they created a general volume decomposition algorithm, which “can be generally applied to models with different shape and topology.”

“Moreover, a support generation algorithm has been developed for multidirectional 3D printing,” the researchers explained. “The techniques developed here can speedup the manufacturing of 3D printed freeform models by saving the time of producing and removing supports.”

Progressive results of fabricating models on 4DOF multidirectional 3D printing system and a 5DOF system realized on a robotic arm.

The research team’s paper made several technical contributions, including their support-effective algorithm, which is based on beam-guided search and can be applied to 3D models with handles and loops. In addition, they also summarized decomposition criteria through their multidirectional 3D printing process and created “a region-projection based method” for generating supports for multidirectional 3D printing.

There are, however, some drawbacks involved when changing from one 3D printing direction to another, such as slowing down the process, which is why the researchers “prefer a solution with less number of components, which can be achieve by considering the following criterion of clipping.”

A comparison of decomposition results obtained from three schemes introduced in this paper.

“After relaxing the hard-constraint of support-free into minimizing the area of risky faces as described in JG, the scheme of generating support is considerately vital while both feasibility and reliability should be guaranteed,” the researchers wrote. “To tackle this problem, we propose a new pattern called projected supports that ensures the fabrication of remained overhanging regions through a collision-free multi-directional 3D printing.”

The decomposed and 3D printed results fabricated by the system with 4DOF and 5DOF in motion.

The team applied their algorithm to several models, and were able to reduce, and even eliminate in some cases, the need for support structures. In addition, their method’s “computational efficiency” was on par with general 3D printing time.

“We present a volume decomposition framework for the support-effective fabrication of general models by multidirectional 3D printing,” the researchers concluded. “A beam-guided search is conducted in our approach to avoid local optimum when computing decomposition. Different from prior work relying on a skeletal tree structure, our approach is general and can handle models with multiple loops and handles. Moreover, a support generation scheme has been developed in our framework to enable the fabrication of all models. Manufacturing constrains such as the number of rotational axes can be incorporated during the orientation sampling process. As a result, our algorithm supports both the 4DOF and the 5DOF systems. A variety of models have been tested on our approach as examples. Hareware setups have been developed to take the physical experiments for verifying the effectiveness of our system.”

Co-authors of the paper are Chenming Wu, Chengkai Dai, Guoxin Fang, Yong-Jin Liu, and Charlie C.L. Wang.

Discuss this research and other 3D printing topics at 3DPrintBoard.com or share your thoughts below.

 

Posted on

Indian Startup Shapecrunch: An App to Let you Get Custom Fit 3D Printed Insoles

Insoles and orthotics generally are looking to be the next area where 3D printing will play a role. As with hearing aids and dental crowns a custom shape needed to fit a patient perfectly can cost-effectively be created through 3D printing. Usually, 3D printing is best at rather small items and insoles are a newer large size than the mass customized things that have been 3D printed thus far in their millions. Insoles have as an advantage however that they’re very flat so require few layers to print, improving the business case significantly. I find it strange that we pay hundreds of dollars for shoes that only come in a handful of sizes. Things such as orthotics and custom insoles can be more costly still. It is clear at this point that 3D printing can provide us with the accuracy, strength and performance needed to endure as a working insole. Whats more with variable density insoles different points of the foot could have different densities through different infill which will give you performance that conventional insoles lack. It is also clear that scanning and 3D scanning could give many people access to custom-made insoles. What is not clear is how to do this and who will succeed in the space. Jabil and Superfeet, Wiiv, Indian startup Shapecrunch thinks it may have the answer by combining 3D printing with scanning using your phone.  We covered Shapecrunch earlier when they first came to our attention in January, Can they succeed where others have failed? We interviewed Nitin Gandhi the CEO of Shapecrunch to find out more.

How did you get started? 

Every 1 in 4 people has some foot problem related to biomechanics such as Flat feet, Plantar Fasciitis etc. Every 30 seconds a diabetic foot is amputated in the world. Moreover, the foot related problems are responsible for back, neck and knee pain. Still getting anything custom made for a foot is a huge challenge. The process of making custom shoe inserts (or insoles) is very manual, has huge setup cost, and takes 30-45 minutes of time for any doctor.

I’m flat-footed, and in 2015 went through the experience of getting an insole.  When the insole came out it was not so good. At that time, since I was already running a 3D printing company, I along with his partners who are mechanical engineers Jatin and Jiten founded Shapecrunch. Later Arunan, a Biomedical engineer also joined them.

Shapecrunch digitized the complete process of making custom foot insoles with 3D Printing and a Computer Vision algorithm.

Doctors use Shapecrunch’s free app -available on android and iPhone to take just 3 pictures of patient’s foot, add patient’s bio and upload a prescription. Shapecrunch using its smart proprietary algorithm converts the images into a 3D model of the insole, which is then 3D printed. The process of taking images and using the app takes just 7 minutes.

For the technology, Shapecrunch did clinical research with the Rehabilitation wing of All India Institute of Medical Sciences (AIIMS) and for a bigger trial, also got a grant from BIRAC.

Shapecrunch started selling in the market in early 2017. So far more than 2000 patients are wearing Shapecrunch’s Insoles. Because everything is remotely done with app, any doctor/patient can download the app, click foot images and prescription pic, Shapecrunch can create custom insoles for many people. As the data is being stored digitally, the patients can order another pair anytime. Every 1 in 4 customers orders another pair for different shoes within 6 months.

What 3D printing technology do you use?

We use FDM 3D Printing technology. All machines are assembled by us so that they can print flexible material perfectly.

What materials do you use? 

Shapecrunch uses flexible 3D printed material for making your customized insoles. Thermoplastic polyurethane (TPU) is any of a class of polyurethane plastics with many properties, including elasticity, transparency, and resistance to oil, grease and abrasion.The upper layer is made from PORON®, a breathable, shock-absorbing material which cushions the foot and has anti-microbial properties to keep feet feeling fresh and healthy.

Whats the workflow for me as a customer?

We are having alliances with podiatrists all across the world who can use our technology to scan patient’s feet, upload prescription and we design and 3D print the insoles. Customers can either go to our alliance partners around their area or can download our app and our in-house team which has orthotist, physio and orthopedic looks at the feet.

What is the benefit for me as a consumer?

We do advance customization which is not possible with traditional ways of making insoles. The computer vision algorithm gives us the boundary curves and machine learning provides us with the inner curves we also take into account age, weight, height, pain areas of the patient. With the machine learning algorithm, we get a variable density profile which goes into making the file 3D printing.

How long do the orthotics last?

Orthotics easily last for up to 2 years for moderate use and 1 to 1.5 years for athletes and heavy users. We do provide a 6 months warranty.

How do you partner with the orthotics community?

As of now, we are participating in medical conferences and exhibiting our product and technology. So far, almost all the podiatrists and physiotherapists care a lot about how it can solve their patients’ problem. We also focused a lot on that.

What kind of ailments are you targetting?

Shapecrunch is making Custom insoles for Flat Feet, Supination, Plantar Fasciitis, Diabetic Foot, Corn and Callus, Leg Length Discrepancy, Knocked Knee and other biomechanical related problems.

 

Where do you wish to roll out the product?

We are already growing fast in India and Singapore and have 50+ clinics using our technology. We are starting in the US soon and plan to have it as our primary market.

Will you integrate sensors into it?

Yes, It’s already under development we are launching it in next 3 months for doctors for diagnostic purposes and as an additional tool for analysis. Later we plan to introduce a consumer version as well.

What about variable density insoles?

All our insoles are variable density. Density at different areas is determined from a variety of parameters such as age, weight, height, pain areas etc.

Will everyone wear these?

More than 2500+ people are wearing shapecrunch’s insoles for foot problems, for sports, marathoners and some just for comfort. For each of our customers, a fully customized solution has been provided to improve biomechanics. So definitely, it should be worn by everyone who needs them.