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Assembly kit for an RC model truck

High-quality Volvo FH16-750 assembly kit on scale 1:14.

DeskProto user Model Engineering in the Netherlands offers product development, model making, prototyping and small series production. The company combines traditional model making skills with the latest technology, including fast CNC milling machines and CAD/CAM tools like SolidWorks, Solid Thinking and of course DeskProto.

screenshot from the Volvo website
The Volvo website underlines the good looks of the FH16.

One of their clients is Verkerk Modelbouw: a specialist in (parts for) Radio Controlled model trucks. They offer a large assortment of parts and of complete assembly kits for model truck builders. Recently they were able to make a big step forward by releasing their own assembly kit for a scale model truck: the Volvo F16-750. This new kit has been developed in a close cooperation with Model Engineering, where Model Engineering constructed the CAD models, designed and created the molds and produced the parts on their in-house injection molding machines.

SolidWorks screenshot with geometry
SolidWorks screenshot with mold halve
CAD drawings in SolidWorks: left the lower front grill, right one mold half for both front grill parts.

The model is fully licensed by Volvo Trucks Sweden and by Michelin tires. This means that Model Engineering could use original CAD data (kindly supplied by Volvo) as a starting point. Still a lot of CAD work was needed: for each scale 1:14 part a completely new CAD model was created, based on the original data.
The next step was designing the mold for each part. Again a complicated job, as many of the molds needed curved parting surfaces and/or moving slides for side actions. And of course all standard mold design issues needed attention too: draft angles, gates, ejection pins, sink marks and so on.

DeskProto screenshot with toolpaths
DeskProto screenshots, showing toolpaths for the grill mold, with very small details.

Several CAM programs have been used in this project; for all cavities the toolpaths have been created using DeskProto. This was done with a small cutter and an even smaller stepover (distance between the toolpaths), like a ballnose cutter with 0.5 mm diameter and a stepover of 0.02 mm. Strategy Parallel, with toolpaths at 45 degrees with the X-axis. Even with DeskProto such calculation can take up to several hours per job. The NC file size for such finishing operation can easily reach 500 MB.

Pieter van Nimwegen of Model Engineering states: "Many expensive 'high-end' CAM programs were not able to reach the required precision: the program would simply crash halfway the calculation, or the resulting surface quality simply was not good enough. DeskProto does an excellent job, at an unrivaled price/performance ratio."

The toolpaths for all geometric details like guiding pins, ejector pins and gates have been created using an engineering-type CAM program.

CNC machining with coolant flowing
The mold on the machine
Machining the cavity in the mold for both front-grill parts.

Machining was done on Model Engineering's three Akira-Seiki PC-700 HSC milling machines, with Mitsubishi Mi745 controller. This powerful controller allows the machine to keep working on the prescribed feedrate, even with toolpaths consisting of many very small G1 steps (like for this grill mold). Many machines will slow down on such toolpaths, as their calculation time needed for each G1 movement simply is too high.

As can be expected, the machining time for each cavity was high as well: 60 hours of continuous machining was no exception. The resulting surface quality of the cavities was very high, though of course for transparent parts and for parts to be chrome plated the cavities needed to be polished to high gloss.

Plastic grill part falling out of the mold
Batch of plastic grill parts
Left the injection mold in action, with a part (white) that was just made, right a batch of freshly produced grill parts.

The grill part was not the easiest one to injection-mold: many holes, separated only by a small amount of plastic. In order to get the part out of the mold undamaged an extra large draft angle was applied and a very large number of ejector pins was used. The parts were shot in ABS (plastic).

The project took longer than expected while it kept growing over the years. Finally resulting in more than 1100 parts for this one truck model only. Total production involved more than 150,000 parts ! A very large stock, that will be reduced now the assembly kit has been released for sale to clients.

Promotion photo bt Verkerk
Promotion photo bt Verkerk
Left the grill part as it came from the mold in white ABS, including the sprue channel (runner). Right the same part after chrome-plating.

A number of ABS parts have been chrome-plated, including the grill. For the grill a matt chrome has been applied, other parts have been done in a high-gloss chrome. Most parts in this kit are in ABS, though when needed other materials have been used, like fiberglass-reinforced polycarbonate, aluminum and rubber.

Promotion photo bt Verkerk
Promotion photo bt Verkerk
The grill (black version) assembled with the front of the cab, and after finishing the complete model.

The project to create this truck model started in 2015. The plan was to release the assembly kit 1.5 year later, using 47 production molds. More important though were the very high requirements for level of detail and for quality, and the determination not to compromise in that matter. As a result the total time for development and production increased to more than 3 years, using 115 production molds.

During the complete development process Verkerk Modelbouw released short videos to show their clients what was achieved. In total 90 videos have been made, still available on YouTube channel VerkerkModelbouw TV. The company is very happy that after this long delay shipping of the kit now has started.

The box is which the kit is shipped
PTwo pages of the manual
The kit comes in this large box, with a detailed "Building instructions" book.

The assembly kit can be purchased in the Verkerk Modelbouw webshop. It is shipped in this large box (58 x 37 x 21 cm). Do not under-estimate the time needed for assembly: this is not a simple kit. The manual with building instructions is a book of 60 pages.

Promotion photo bt Verkerk
Promotion photo bt Verkerk
The resulting 1:14 scale model of the Volvo F16-750.

The new truck model has been presented on the InterModellBau show in Dortmund (Germany). This show claims to be the world's largest exhibition for model making and model sports. Visitors to this show (though already used to seeing very high quality models) received this new model with great enthusiasm as a new milestone in truck models.

Presentation of the new model on the InterModellBau (the last shot in this one-minute video).

This product lifts model truck making to an unprecedented new level, with amazing details like natural suspension (air) and damping, all lights working, a working cardan shaft and differential, real rubber Michelin tires, realistic motor sound, and much more.

Pieter van Nimwegen concludes: "DeskProto is very good in machining (doubly) curved surfaces. The geometry of a truck contains virtually no flat surfaces, which made DeskProto the ideal CAM program to complete this project."