MODELS ON DEMAND

From making tools and parts to creating replicas of museum violins, 3D printing offers luthiers both practical and educational possibilities. Harry White speaks to violin makers about how they are embracing the technology

'An advantageous alternative to plaster casts’: Joshua Beyer

What is 3D printing? Technically speaking, it’s the process of fabrication (also known as ‘additive manufacturing’) in which a computerised, digital design is made by machine that adds successive layers on to a flat surface to create a three-dimensional object. Thus far, the conversation around 3D printing within a musical milieu has been dominated by how far it can be used to create concert-worthy instruments. But this has taken focus away from an arguably more intriguing dimension. As Harry Mairson, a professor of computer science at Brandeis University in Massachusetts, wrote in this magazine (Making Matters, July 2021): ‘Violin making depends on having good tools’.

The 3D printing of instruments and the dataset that enables it are increasingly being seen as important factors in enhancing the contemporary luthier’s knowledge and workflow. ‘I’m not a professional violin maker; I’m a college professor who’s kind of fanatical about making musical instruments,’ says Mairson. ‘But I’m going to Cremona this year with the support of the Museo del Violino and the Istituto di Istruzione

ALL PHOTOS JOSHUA BEYER

A freshly carved scroll next to its 3D-printed counterpart

Superiore Antonio Stradivari Cremona to talk to violin makers, students and teachers of lutherie about how to use radiology to look at CT scans of famous instruments. With CT scans, they can see the archings and the outlines. If you’re working on a cello and you want to know what the overstand should be, you can literally see what it’s like on Stradivari’s “Stauffer, ex-Cristiani” or his “Countess of Stanlein”. It’s just like having those instruments in your shop, right there to learn from. I’m convinced that applying data from CT scans and learning to use 3D printing technology will be useful to violin makers.

For example, with the data that drives a 3D printer I can rapidly fabricate prototypes of archings that I have designed geometrically for assessment. I can look at a prototype, look at its reflection, feel it, take measurements. And there’s a huge difference between that and studying scan data of a modern, imperfect instrument or something really old, and then digitally sanding or smoothing it to enhance its symmetry.’

‘WITH A QUALIT Y CT SCAN, A RELATIVELY ACCURATE 3D PRINT OF A VIOLIN SCROLL CAN BE MADE FOR UNDER $30’

Joshua Beyer, a violin maker in New York City, was drawn to 3D printing as an advantageous alternative to plaster casts.‘Antique instruments are becoming more and more scarce from makers’ everyday workbenches, and the chances to make plaster casts of the arches and scrolls are occurring even less,’ says Beyer.‘But with a quality CT scan, a relatively accurate 3D print of a violin scroll can be made for under $30. Using the 3D-printing process avoids possible damage that can occur to the instrument during casting. Another common problem with casts and their moulds is that they lose their dependability and, over time, errors begin to develop. With 3D printing, every item is a fresh print and these issues are avoided.’ And Beyer is actively using 3D printings in his work. ‘To aid my own making, I have 3D-printed scrolls, plates and full violin bodies,’ he says. ‘And I use these the same way you would use a plaster cast: it is a model for me to reference while carving. They’re not perfect but the information contained is incredibly helpful, especially when used in tandem with photographs and measurements of the original instrument. Some people I know have built their own 3D printers and in the long run this may be the most economical and convenient option. Luckily there are a number of services online that allow you to upload files and get 3D prints mailed to you within weeks. A simple search for “3D printing service” will bring up many options. Violin making schools and non-profit organisations related to the trade are in a perfect position to help normalise this technology and provide opportunities to makers.’

Harris Matzaridis, an additive manufacturing consultant, believes that the benefits of 3D printing to the working luthier are numerous: the technology can create cost-effective customised tools for repairs or violin making; provide access to the detailed geometric and colour information of historic violins; and act as an education tool for the design decision-making process. ‘Imagine the following study scenario,’ says Matzaridis. ‘A 3D-printed violin plate of specific archings and thickness that gets printed twice from the same material will vibrate pretty much the same way, whereas two wooden ones will rarely do so, even when made from the same log.

Now, we print a new extra plate while introducing a small geometry change and then examine vibration differences. If we repeat this process multiple times with more detailed changes, the maker can get a better understanding of the impact that a specific geometry change has on how the violin plate vibrates. I call this “parametrisation” of violin geometry features and their effect on vibrational characteristics, to help in the design process of violins.’

Stephen Quinney, a violin maker from Toronto, cites the educational benefit of 3D printing in the development of his own work. ‘I started working with 3D printing when I realised that I had an archive of CT scans of instruments that I could turn into real 3D objects to use as reference materials for making,’ he says. ‘Using Horos software, which is free, I was able to create STL [Standard Tessellation Language] files from the CT scans that I sent to an online service, and a week later I got printed parts back. When we can get our hands on plaster casts of a scroll or a back or belly of an instrument, they are useful to have as reference materials when making a new instrument.

But it’s hard to get hold of casts and there are archives of CT scans available in museums like the Library of Congress in Washington DC. The better the scan, the better the print.But old scans are still useful, even if they are not the sharpest.

‘I wanted to try to do the printing myself since the online services are somewhat expensive, so I thought I would see what I could do with a cheap $300 3D printer of my own,’ Quinney continues. ‘The online services have lots of different types of printers that you would not have at home and sometimes you need those. But having a small additive printer in the workshop was fun to play around with and the more I used it the more I realised I could do with it. The biggest benefit for me with 3D printing is being able to print something that I need when I need it, rather than having to order it and have it shipped.

And in Canada, the shipping costs are often prohibitive. For example, I had a customer who wanted a new cello endpin installed and I had the endpin she wanted in stock. When I went to fit it, I realised that I had already used the plastic cone that is used to fit the pin into the hole. The maker of the endpin was in Colorado and shipping a part that costs a few dollars to Canada was going to be so expensive. I was in a bind but realised that I could quickly draw it and print it, so that’s what I did. It worked perfectly. It took 10 or 15 minutes to draw and then half an hour to print. But it got me out of a bind quickly and cheaply.

‘I have also printed soundpost measuring gauges. I used to use ones that I made out of brass. They were awkward to make and often scratched the varnish if you were not careful. After travelling to a convention, I lost the brass gauge I had used for years. I didn’t have any brass stock from which to make another so thought I would try to draw one and print it. The first attempt ended up being too flexible since the brass is stiffer than the PLA filament [one of the most popular plastic materials for 3D printing]. So I revised the design a couple of times and came up with a perfect version that I use every day in my shop.

‘VIOLIN MAKING SCHOOLS AND NON-PROFIT ORGANISATIONS RELATED TO THE TRADE ARE IN A PERFECT POSITION TO HELP NORMALISE THIS TECHNOLOGY’

Would Stradivari have made use of 3D printing technology?

HARRIS MATZARIDIS

3D-printed f-hole templates by Harris Matzaridis

PHOTOS HARRIS MATZARIDIS

And I have multiple versions to measure the position of a soundpost behind the bridge foot at different distances. They work wonderfully, and if I break one or lose one, then I can print another in a few minutes. I also made some new closing clamps for clamping the back and belly of an instrument to the rib structure. The commercial ones are very expensive and for the upper C-bouts, the curves are a bit too shallow. I always thought about trying to make one with a tighter radius. So I sat down to draw it. It took a few attempts to get it right but I now have a good working model, and with the addition of a piece of threaded rod and a nut, I have my own custom closing clamps.While drawing this design I realised that I could print threaded holes all ready for the threaded rods. I think that being able to print reference material to use in making is very helpful, and the way you can easily design and print tools and parts saves time and money.’

Joseph Curtin, a violin maker from Ann Arbor, Michigan, has also seen great use for 3D printing in economising and customising violin making tools. ‘I use 3D printing to make some parts of the Impulse Measurement Rig, a workshop tool that allows makers to measure the sound radiation of their instruments,’ he says. ‘Because this is a very limited market, being able to print parts as needed and modify them from one iteration to the next keeps the cost down and satisfies my own interest in continually evolving the design. For my ultralight instruments, the ability to print one-off castings of parts out of bronze is invaluable.’ Curtin believes the technology is still on the margins of the trade but that this could change. ‘3D printing remains, at least for now, somewhat peripheral to violin making, except perhaps for tools and jigs, because most of it involves polymers that are unsuited to the construction of the instrument itself. This may well change as the technology progresses. What is transforming lutherie right now is 3D scanning and modelling, combined with CNC milling. As individual makers may not be interested in owning and running all the associated equipment, specialised shops tha support makers in this way make a lot of sense. These shops will no doubt have 3D printers that allow quick “previews” of parts.’

‘FOR MY ULTRALIGHT INSTRUMENTS, THE ABILIT Y TO PRINT ONE-OFF CASTINGS OF PARTS OUT OF BRONZE IS INVALUABLE’

In addition to the practical workshop benefits of 3D printing, Mairson believes it’s in the area of curatorship that the technology could have its most profound implications.‘Take the Museo del Violino in Cremona,’ he says. ‘It has these fabulous instruments, and has an incredible responsibility as a conservator. These instruments can’t be available to the general public to measure and to touch. But if the museum also has a plastic facsimile that’s good to tenths of a millimetre, then the museum can say, “Here you go, don’t drop it.” I printed a full-size replica of the “Stauffer, ex-Cristiani” and gave it to the curator of the museum and said, “The next time somebody wants to see the cello, hand them this!” I had the replica in my apartment in Cremona and I invited some violin makers over.

One of them started touching it and said, “Oh man!” A violin maker’s hands are like data devices. When somebody makes an arching, they put their hands over it to try and remember what it feels like. But if you did this on the original, the guards would not be happy. So 3D-printed facsimiles are a fantastic way to protect valuable antique artefacts and give people all the information they need. You can have the best of both worlds.’

This sounds compelling. But while there might be practical and economic obstacles to 3D technology in every workshop, resistance of a more political colouring is proving more problematic. ‘For the longest time, people have been incredibly concerned about letting out data about these instruments,’

Stephen Quinney’s design for a cello endpin cone

How the cone looks when printed and fitted on the endpin

ALL PHOTOS STEPHEN QUINNEY

says Mairson. ‘There’s a tremendous worry that if this information gets out, then there are going to be mass-produced instruments based on it that will do irreparable damage to artisanal violin making. I don’t believe that at all! I have analysed the CT scan of the “Stauffer, ex-Cristiani” with visualisation software more than anyone ever will, and I am yet to look at some detail and think, “Right there is the secret of Stradivari.”

It’s a beautiful old cello. But no one’s going to see this data and say, “Let’s mass-produce this – all this geometry and data is the magic formula.” It just doesn’t work like that; it’s impossible. To those expressing genuine concern about how technology could prompt mass production and compete with the work of the artisan, I don’t think we are anywhere near where a machine can do what a luthier does. And a big reason is that the material used – wood – is so non-homogeneous. As to the hypothetical, quasi-dystopian exact reproduction of a 300-year-old instrument, with its torquing, twisting, deformation and restoration over centuries – why would you carve this irregular history, with or without a CNC machine, into a new piece of wood? It makes no sense to me.

‘In the artisanal making of a stringed instrument, you need to be able to interpret with your hands and tools what is in your mind’s eye,’ Mairson continues. “What am I trying to do?” is every bit as important as “How am I going to do that?”, since even the best technique relies crucially on intention. I believe that the most significant value of technology is in its use to refine what is in the mind’s eye, a development that has traditionally taken decades.

Technological tools such as CT scanning and 3D printing facilitate climbing that learning curve. They help us think. This is how I’ve used them and why they appeal to me.In turn, iconic, historical instruments are incredibly important study objects, whether or not you are trying to make precise copies of them. With this technology, we can protect the instruments and also learn so much from them. In fact, this is the essence of noninvasive curatorship.’

3D-printed copies can also be easily packaged and shipped

‘Only a few years back, I asked a master luthier, “What makes a master luthier?”’ says Matzaridis. ‘He replied, “I have no idea. I have lived and survived in this competitive profession with the feeling of merely having the instinctive ability to make the same mistakes over and over, again and again, violin after violin after violin.” My point is, violin makers sometimes give me the impression they know what to do but not exactly why they do it, and they know how to keep their craft alive but not exactly how to make it progress further. And I have a feeling that this is because they serve a lost art that is just being

rediscovered. The evolution of violin making seems like a process of accidental mutations, where makers copy violins and a small percentage during copying get a different twist, which luckily works better, and so on and so forth. I firmly believe that 3D printing can help violin makers towards the very end goal, of finally gaining a deep understanding of why the design of the violin is as it is.’