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Since the mid-1990s, formwork solutions with integrated magnets have become established throughout the industry and since then numerous formwork systems have been developed for a wide variety of tasks. Many of these are now standard equipment in precast plants around the world. Ratec continues to be one of the market leaders when it comes to particularly complex formwork requirements with demanding framework conditions, such as in automated production. One of these complex requirements for a formwork solution can be that the formwork must shrink for the demolding process in order to be released from the concrete safely and without damage.
The shrinkage principle is more familiar from the production of room modules, where the formwork core usually has to shrink in order to be able to lift the concrete body. However, there are also applications in the production of flat precast concrete elements. As a rule, the following practical cases require a shrinkable solution:
- Concreting on both sides, with or without additional profiling on the formwork profile
- Shuttering of recesses without bevelled edges
- Shuttering of complicated profiles
As a leading manufacturer of magnetic formwork solutions, Ratec has already developed tried and tested solutions for these applications, which are presented below.
Robot-compatible shrink formwork for garden and landscape elements
High-quality, aesthetically pleasing elements for the design and embellishment of gardens and outdoor facilities place particularly high demands on surface quality and low fault tolerances on the production side.
Ratec was entrusted by a manufacturer with the task of developing a robot-compatible formwork that can be concreted on both sides and can be stripped on all sides without breakage, even when using chamfer strips. This is achieved by means of a shuttering profile with movable side panels that automatically fold down and shrink when lifted. The shuttering profile can therefore be lifted out without damaging the element, despite the chamfer strips on both sides of the base.
Shrinkable formwork for window and door recesses
Windows and doors are traditionally topics that can always pose challenges on the formwork side and are therefore often solved by the customer themselves on an individual basis.
One of the latest developments, particularly for vertical production in battery or room module molds, is a shrinkable frame that can be used for door and window cut-outs. The solution was used for the first time together with the 3D mold kit for the production of room modules for a modular house project in Singapore. Other customers, including in Germany, are now using the shrinkable window formwork. The main area of application is the efficient shuttering of recesses in large quantities, especially for standard window sizes.
The steel frame is manufactured in the dimensions requested by the customer and consists of two halves and two separate corners. To demold, first remove the conical corners. The two halves of the window can then be mechanically shrunk together and removed. This enables damage-free demolding. The process of shuttering and deshuttering is significantly accelerated. The solution is suitable for both vertical (battery mold or room module mold) and horizontal production.
The solution has now been supplemented with side parts that allow the size of the frames to be adapted to other lengths, which increases flexibility for the customer.
Damage-free demolding thanks to the shrink principle, even with manual formwork handling
There is another very simple but effective solution for manual shuttering, which can also be categorised as shrink formwork in the broadest sense - the window corner. This is a corner bracket for fixing and damage-free demolding of recesses that are clad with wood. The wood is mitre-sawn for this. The side sections of the recess formwork are inserted into the corner and fixed in place with a star grip quick release screw connection. After concreting, the screw connection is first loosened and then the formwork legs are pulled out upwards. The wood-planked corner remains in the element and can be removed at the end. It can be combined with all wood-planked formwork solutions, such as PSV, MST and Easy Form. The advantage: Both the window corner and the planked side sections can be reused several times before new planking is required. The element and formwork remain undamaged.
The continuous further development of magnetic formwork technology and the intelligent adaptation to both manual and highly automated production processes make Ratec a leading supplier in this field. One of the main strengths lies in the development of customised solutions for sometimes difficult problems, which in the best case scenario will later become a standard solution.