With more than 40 years in the business, Velleman is a well-known electronics kit company. In 2013, Velleman entered the world of 3D printing with the K8200, an open source 3D printer kit. Now the team has followed that with the release of the K8400 Vertex, a significant advancement from the K8200.
Price $799
Build Volume 180×200×190mm
Bed Style Cold glass with custom BuildTak sheet
Temperature Control? Yes
Materials Numerous
Print Untethered? Built-in SD card slot and LCD makes it easy to print on the go
Onboard Controls? Yes — onboard LCD with control dial
Host Software Custom version of Repetier-Host
Slicer CuraEngine in Repetier-Host
OS Windows only for their slicer, but should be able to be used with other cross platform slicers
Firmware Marlin
Open Software? Yes
Open Hardware? Yes, CC-BY-NC-SA 3.0
DUAL EXTRUDERS THAT WORK
A welcome feature of the Vertex is its optional dual Bowden-style extruders — while most DIY and kit machines have had the ability to use two extruders, Velleman has now made this an official component selection on the K8400, which is how we tested it. The Bowden setup allows both heads to be placed close to each other so the user loses less print space overall, while still having the power of dual extrusion. In our testing, we did not find uneven nozzles to cause printing problems with the Vertex. Two smoothly rotating, integrated spool holders compliment the dual extruders.
On the downside, I did find the extruders a little hard to load. I think a minor redesign of the cold end could help create a better path to make loading much easier.
NEW MECHANICALS, LARGE BED
The K8400 also introduces a re-engineered carriage system. Gone is the fixed extruder that only moved on the Z-axis on the K8200. The designers replaced it with a printhead that moves in the X and Y dimensions and a bed that moves in Z with mechanics similar to those of the community-beloved Ultimaker.
All of the linear motion components on the Vertex are built with igus polymer parts. This is a major upgrade over traditional roller bearings that need regular maintenance and have a much shorter lifespan. These polymer bearings also tend to be much quieter, a pleasant addition for in-home use.
While the Vertex doesn’t sport a heated bed, the glass build plate has a custom BuildTak coating, helping with adhesion for numerous materials. The large (180mm×200mm) plate is easily removed from the printer by swiveling four metal clips out of the way. It doesn’t have an auto-leveler, but its manual three-point leveling system is much easier to use than the four-point arrangements that used to be common on many machines.
CUSTOM REPETIER SOFTWARE
For slicing and printer control, Velleman has packaged their own distribution of the popular Repetier-Host. This bundle uses the CuraEngine (the back-end slicing portion of Cura) for slicing, and the custom profiles for the Vertex are bundled inside. Unfortunately, they currently only offer this package for Windows — though this is something that should be easily fixed since Repetier and Cura are both multiplatform pieces of software.
Don’t lubricate your polymer bearings. This can actually cause buildup in them that will shorten their lifespan.
Bend your filament to straighten it and take any curl out of it when loading. This will help guide it into the Bowden tube.
WHY TO BUY
For those looking for a dual extruder 3D printer with lots of other bonus features but still want to build their own, the Vertex is hard to beat … especially at this price.
PLEASING RESULTS
The overall print quality from the Vertex was very good. The surface qualities gave quite legible text on models like the mini Makey robot. Our overhang test was also excellent. Where the printer fell down was on bridging, and any time it came to a short layer time. By default, the slicing profile has a 10-second minimum layer time. This means that on quickly printable layers like the single-walled box of the Z probe, the Vertex will move its print head away for a moment to let the layer cool. This leaves an ooze trail behind, and results in inconsistent printing when starting a new layer. This can easily be resolved by adjusting the minimum layer time settings along with the retraction settings. Hopefully Velleman will continue tweaking their profiles to optimize for this. (See our testing methodology.)
IT’S A KIT
The Vertex, like Velleman’s other products, is sold as a kit. However, the Velleman team had already assembled the unit that we received for testing. For those building their own, the company has created a very detailed set of documents. They also have an extremely active online forum with tips and tricks from other owners.
CONCLUSION
The Vertex is a great option for anyone who still wants the experience of building a kit machine. It has plenty of bonus features that make it stand out, and at its price point, it’s a lot of machine for the money.
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