Our technology

The 3D-printed last from Dreve offers outstanding properties for the production of custom shoes. It is available for you on short notice without long delivery times and is manufactured by us in an energy- and resource-saving way. At the same time, it is in no way inferior to traditionally crafted lasts. Thanks to the digital workflow, you always receive a highly accurate product that can be reproduced at any time.

Properties

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Resilience
An important requirement for the shoe last is its resistance to mechanical stress, which is particularly enormous when molding the sole. In this respect, the 3D-printed last by Dreve convinces with maximum stability even under punctual load. The internal honeycomb structure ensures that stability is provided and the last remains pleasantly light.
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Sanding
If adjustments to individual lasts are necessary, the removal of material becomes an important step. Belt or flap sanders, powered by machines, are employed to effectively eliminate material, leading to substantial material removal and heat generation. Both are factors for which Dreve's 3D-printed last has been optimized. The material has remarkably low thermoplastic properties and enables grinding without lubrication and without rapid clogging of the abrasives. Sufficient wall thickness prevents exposure of the internal structure during grinding.
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Filling and bonding
The ultimate objective in orthopedic custom shoe production is to achieve the best possible, personalized fit for each patient. To ensure optimal comfort during wear, adjustments to the last may be necessary in the early stages of the manufacturing process. Despite the precision of highly accurate scans, potential pressure points, which may only become apparent when the patient tries on a trial shoe, cannot always be anticipated. In such cases, the last can be enhanced and contoured using either putty or cork strips, common materials that seamlessly integrate with Dreve's 3D-printed last. Both, putty and cork strips, adhere flawlessly to the resin, allowing for precision machining and sanding to create an imperceptible, smooth transition to the initial last.
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Thermoforming
In order to be able to make a perfectly tailored shoe, a fitting with a trial shoe is an established procedure. Transparency allows the orthopedic shoe technician to see if there are any pressure points and to assess the general fit. Traditionally, the trial shoe is produced using the thermoforming process. The film employed is heated to enhance its flexibility significantly. Subsequently, the heated film is stretched over the last within the thermoforming machine and precisely adhered to the last through the assistance of a vacuum. The 3D-printed slats from Dreve efficiently absorb and dissipate the heat transferred during the process. Once the material has cooled, the last can be effortlessly extracted from the mold and employed directly for subsequent shoe production.
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Tacking
Working with compressed air-driven tackers on the last is essential for rapid work progress. To seamlessly insert tacker needles into a component, the material must possess properties that facilitate easy insertion while enabling effortless removal. Ideally, the material should retain stability even after staple removal, allowing subsequent needle insertions for tasks like crafting another shoe.  Dreve's 3D-printed last can guarantee all this. The optimized material properties in combination with a standard wall thickness of 8 mm ensure ideal retention of the needles in the last at all times.
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Nailing
Custom-made shoes must adhere to the highest quality standards to guarantee optimal patient care. Specifically, premium fabrics, with a focus on high-quality leather, are employed in the crafting of these personalized shoes. During the formation of the shoe upper, the selected material is stretched over the last and securely fastened to the underside using nails. It is essential that these nails can be effortlessly inserted and removed while effectively securing the upper material in place. The 3D-printed last from Dreve fulfills this crucial aspect. The adjusted wall thickness ensures that the nails consistently maintain a secure grip on the last. Furthermore, optimized material parameters contribute to the facile and minimally damaging removal of the nails.
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Highly resilient connection
The dimensional accuracy of the lasts in the production of custom-made shoes is essential for achieving an optimal fit for the patient's foot. To ensure the absolute stability of Dreve's 3D-printed lasts at their connection points, a robust connection mechanism comprising two elements is used. The first element is the stair-shaped separating cut ensureing that load-bearing forces are transferred over a large area between the two slat parts. The second element involves a screw connection component integrated into the honeycomb structure on the inside of the last during the modeling phase. This element effectively binds the last parts together, ensuring a secure connection. In the frontal region of the last, two stainless steel threaded inserts are typically embedded, serving as anchor points for M8 screws—also made from stainless steel. The same screwing technique is used for a taller, three-part leg slat. The combination of these connecting elements results in a form-fit, heavy-duty connection. The use of stainless steel in the design not only guarantees a wear-free experience but also facilitates smooth opening and closing of the connection.
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Absolutely stable
The long-lasting stability and durability of shoe lasts play a key role in ensuring the consistent production of high-quality, customized shoes over an extended period. Traditional wooden lasts may experience slight variations in response to fluctuations in temperature and humidity, and 3D printed lasts from alternative manufacturing processes often exhibit water absorption and subsequent diminished mechanical properties. In contrast, the Dreve last, crafted from light-curing plastic, remains free from these deficiencies. It retains its resilience and dimensional stability over the years, maintaining the same level of performance as it did on its initial day of use.
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Reproduction and new printing
All lasts produced by Dreve through 3D printing processes must be accessible in digital format for production purposes. The digital data can be generated through various methods, with direct digital impression by a scanner, scanning a plaster cast, or creating a last based on measurements being the most common approaches. The advantages of the digital last are obvious: convenient storage for decades without the need for physical storage, immediate reproduction or new printing in case of loss, damage, necessary major changes to the last, or the simple adjustment of individual areas. All these factors advocate for the use of digital lasts, thereby simplifying and streamlining the management of the large amount of patient data.

Why DLP Printing?

Waste and sustainability are increasingly significant and crucial issues in today´s world. Wood moldings fit ideally into this profile of requirements, but are manufactured through subtractive methods, leading to a considerable amount of unused wood waste. Additive manufacturing meshes precisely with this approach. In the manufacturing process generally referred to as 3D printing, the component is built up layer by layer, i.e. material is gradually layered on top of one another, and only in the area that will later constitute the component. The material used is therefore incorporated into the final component almost completely and without waste.

In the FDM printing process, the material used is heated and recorded layer by layer with a nozzle in the form of a melted plastic strand. Two things in particular are disadvantageous here: Firstly, the nozzle has to approach each individual point within a layer once, which means high production times for large components. Secondly, the material cools after deposition, which means that the next layer, again hot and molten when extruded from the nozzle, is deposited on a cold layer. Stresses and a less than ideal layer bond, leading to mechanical weak points, are the result.

In 3D printing with light-curing plastics, material is cured by means of UV light and thus chemically shaped by molecular bonds. The bond between the layers is also based on cross-linking of the molecules, which makes the layer bond very stable and gives the finished component almost isotropic properties - the component can be loaded equally in all directions.

The benefits of these advantages are consolidated in 3D-printed lasts by Dreve.

Sustainability

Nowadays, there is an increasing awareness of sustainability and ecological products. This idea affects both, the private and commercial sectors - and therefore also the work of orthopedic shoe technicians in their workshops. Shoe lasts are no exception, even if the aim should always be to use the last for as long as possible and for as many pairs of shoes as possible for reasons of efficiency alone, provided the patient's foot does not change significantly.

However, if this is the case, the disposal of the last must be resolved. In this context, our 3D-printed last is on par with the wooden last in every aspect. The resin used is free from toxins, allowing for the disposal of the molding with regular household waste. Thermal recycling for generating heat or electricity is seamlessly feasible. Alternatively, you have the option to return the skirting board to us for recycling through Dreve.

Disposal options of the 3D-printed last from Dreve:

✓ Disposal via household waste 
✓ Thermal recycling possible without any problems
✓ Return to Dreve for free disposal

Our experts

Opting for 3D printing is an innovative step in your overall workflow. However, the initial stages, particularly the commencement and implementation, can pose challenges, not only for beginners. Our additive manufacturing and 3D printing experts are happy to support you on your way. We'll be pleased to guide you expertly through the process. For more than seventy years, Dreve has stood for high-quality and reliable products in medical applications. 

As a provider of medical products, our top priority is ensuring the absolute satisfaction of our customers. Our experts therefore offer real added value for you – whether you are an experienced user of digital technologies or an ambitious newcomer. Feel free to contact us at any time!

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