Zone RV may be a relatively new name in the caravan industry but that’s not the impression you get judging by the well-built range of caravans that come out of its Queensland factory. Indeed, quite the opposite, because the principals behind Zone RV have gained their experience over years in related industries including marine and transport, as well as in caravan manufacturing.
Having reviewed Zone RV’s 20.6 Off Road (CW548) and 18.6 Off Road (CW552) and come away suitably impressed, we thought it was time to take a closer look at the company’s manufacturing process to see how these unusual looking vans are actually built.
Although a Zone RV caravan comprises a chassis with a caravan body on top, that’s about the only similarity it has with a conventionally-built caravan. Much of the build technique is very different to the norm, so Zone RV managing director Matt Johns was kind enough to take us on a factory tour of Zone’s Coolum Beach, Qld, HQ to talk us through the process.
After consultation with the customer regarding the chosen layout, specification level and colour scheme, Zone RV’s build process gets underway using a computer-aided design (CAD) system. This is where it all starts to come together and CAD is very much a part of the entire process – everything from CNC-machine precision-cutting to a comprehensive Quality Assurance program.
And it’s the latter that underpins Zone RV caravan production. Each part of the caravan build process, of which there are about 600, is tracked, with key employees responsible for signing off on components as they are completed. The system is also designed for tracking faults, should they occur, back to their origin.
The purpose-built chassis is designed by Zone RV to be strong and lightweight. There are 150x50mm (6x2in) main rails and a combination of 50x50mm angled steel and rectangular hollow section (RHS) cross members. The use of the angled steel reduces the weight of the cross members.
The chassis design is similar to that seen in European vans, in that there is less steel than might normally be used in Australian designs. This is because of the use of a monocoque construction technique, where the load is spread throughout the entire structure, not just the chassis.
Another point of note is that all the pipe work and cabling is either run directly under the floor or through the chassis rails. To allow for the under-floor piping, chassis cross section members are set low and not all are used for the floor mounting; raised sections in the middle of the RHS cross members support the floor.
Up front, purpose-built braces are fitted under the drawbar rails to eliminate any weak spots where the drawbar meets the van body.
Despite these design differences, there are still a few familiar components to be found on the chassis structure, including Vehicle Components Cruisemaster independent suspension and Al-Ko corner stabilisers.
The floor is as an integral part of the chassis structure. Resin infusion techniques are used for the hand-built floor panel – it is not just a simple foam core with an outer skin. Included in the floor construction are two troughs for drawing cables through and the necessary plumbing drainage fittings.
JUST IN TIME
There is no production line process in the Zone RV factory, so each van has its very own bay from start to finish. Once work on the chassis is complete, it’s wheeled into position and jacked up. The wheels are taken off and the chassis is laser aligned so it’s completely level. It is then tied to the floor by turnbuckles to ensure there is no movement during the build.
All of this is an important part of the process and ensures everything fits together perfectly – a 5mm gap at floor level can mean something much greater at roof level. Safeguarding against movement during the cabinetry fitting and body construction phase is vital because no screws, staples or fastenings are used; instead, the entire caravan structure, including the floor, chassis and cabinetry is bonded together using a polyurethane glue.
Zone RV uses what might be termed a ‘just in time’ process throughout the entire caravan build. So while the chassis and floor are being put together, the cabinetry is being assembled in a separate section of the factory.
There’s no timber to be seen anywhere here, which sets Zone vans apart from many, many others. The cabinetry is built with aluminium framing and Signbond 2mm aluminium composite panel. All the framing is designed to slot together and both the frame and the composite panel are bonded during the assembly process.
The aluminium framing is custom-made for Zone RV and is designed to include concealed LED strip lighting, which improves the overall lighting effect without extra surface-mounted light fittings. The cabinetry is also designed to include cavities for power cabling and many of the cabinets are pre-wired to save time during the overall van construction process.
Once the chassis is in position and the floor bonded to it, the body construction can commence. Zone RV uses the ‘inside-out’ method, which means all the pre-formed cabinetry work is put into position first, then all the electrical wiring and plumbing is added in and, finally, the walls and roof are added.
Because the many holes, cavities and cable runs are designed in during the initial construction and design phase, although not impossible, customer changes mid-build aren’t always easy to accommodate.
A benefit of using the inside-out method is that after all the electrical cabling, water and gas pipework is installed, it can then be fully tested and, without the walls and roof in position, any faults that show up during testing are much easier to rectify.
The walls and one-piece front, rear and roof panel consist of double-sided gloss fibreglass skins that sandwich a high density XPS foam core. With the walls in position, the installation work on the van body continues. As you might imagine, getting the one-piece front, rear and roof panel exactly in position requires total precision and, a bit like a model kit, the panel comes with ‘fold lines’ to ensure it fits around the walls accurately. Both walls and the one-piece panel have all the necessary window, vent and door holes pre-cut by CNC machine.
With the roof and walls all in position and bonded together, the final assembly and testing can take place.
Finally, a brand new Zone RV caravan rolls out of the factory door. It takes about 10 days once construction starts but, of course, the overall design work and customer liaison takes somewhat longer.
Zone RV likes to make sure its customers fully understand the caravan they are buying and so have a customer handover time of at least six hours and offer a night at the local caravan park as part of the familiarisation process.
The full test appears in Caravan World #554 August 2016. Subscribe today for the latest caravan reviews and news every month!