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In the beginning, there was the tube

Generally, tubes are circular in cross-section. However, in special cases and with the tubes for the frame of the impec in particular, it is really not that simple..

The perfect racing machine – according to ancient wisdom – transforms maximum possible energy invested by its rider into direct propulsion without bringing its own weight to bear. The frame needs to be light and rigid and yet stable and agile at the same time.

in order to bring these attributes together in an optimum ratio in the impec, we first concentrated on the design of the frame tubes. We wanted to design each individual tube in such a way that it will optimally absorb and distribute across its entire length all the stresses that are brought to bear.

This wasn’t actually a new idea for our engineers and designers. For a number of years, they had been working on technologies so that we could optimize frame tubes from composite material specific to load. The terms “Tuned Compliance Concept” and “Force Specific Tubing”, for example, represent BMC innovations that provide for greater stability, accurate handling and increased rider comfort and were of key importance in the development of the impec.

We knew pretty well where a frame needed to be more rigid in order to optimize the efficiency of its rider. We knew how the perfect frame tube needed to be designed – and incidentally it is very rarely round. and we knew that such perfection would remain Utopian without the perfect manufacturing process. it was time to develop Load Specific Weave.

The Load Specific Weave Process


impec Technology No 1 is the Load Specific Weave process – LSW. This robot-controlled process creates the frame tubes for the impec. Each of them is manufactured with absolute precision and made-to-measure according to specification with verifiable accuracy...

LSW is the name of a complex three-stage process at the end of which is the perfect frame tube. in brief, the three stages are as follows: weaving, resin injection and cutting – and from these stages comes a humble, flawless carbon tube that only needs to be lacquered, printed and attached to other equally faultless tubes to make the perfect frame.

The strict use of digital technology results in absolute transparency in Load Specific Weave. To provide for this transparency, each workpiece carrier is equipped with a data matrix which contains all the programs for the different process stages that the frame tubes of the impec pass through. The system gives the various robots their commands and at the same time records all the relevant data for each individual workpiece.

Load Specific Weave means

  • defined and controlled fiber orientation
  • consistent angles over different cross sections
  • different angles in the same cross section




In a more detailed version, the production of the impec commences as follows: an industrial robot picks up a material carrier with the positive mold of the tube that is to be produced. it then feeds this core to a radial braiding machine as up until now has been similarly used mainly in the production of steel cables. The data matrix is read off and the weaving process begins. More than 100 bobbins loaded with wafer-thin threads run through the machine along sinusoidal paths to weave a seamless tube of carbon fibers around the positive core at the center of the machine. The material density and arrangement of the fibers is determined here by the rate of advance and the mold of the positive core. The rate of advance varies according to the specific load for which the tube is configured at this point. When the carbon structure is fully woven, the tube is cut off, the material carrier retracts from the radial braider and another core takes its place on the machine.

Resin injection

in the next stage of production, a tube is formed from the made-to-measure carbon sleeve. To achieve the required production quality, we have developed the first fully automated resin injection process in the world for composite materials. Although this is largely a strictly guarded commercial secret, it would be hardly possible to continue the story of the creation of the perfect frame without a few key details.

Central to the second stage of the process are the female molds of all the tubes from which the frame of the impec is created. in these molds, the resin infusion of the carbon structures takes place under absolutely controlled conditions. For this process, the positive core with the previously load-specific woven carbon sleeve is fed into the corresponding mold. A special 2-component resin is then injected through a mixing tube at the lower end of the mold. The workpiece is then left in the mold for as long as it takes to complete the curing process.


We now move on to the third and final production stage of the Load Specific Weave process – cutting the tubes to length. This process is also fully automated and prepared and carried out with extreme precision by industrial robots. Step 1: The tube is separated from the mold together with its positive core. Step 2: The material carrier with the positive core is removed from the tube. Step 3: a precision saw with diamond blades cuts the tube to its final size. Step 4: The finished tube goes for final inspection and then to the paintshop.

The gordian knot

We knew what we wanted to do. We knew that we wanted to manufacture the perfect frame tubes. But what this perfect joining together of the tubes would ultimately look like was a completely different matter..

When the aim is 100 % performance, then to get there you need 100 % quality. and when the aim is 100 % quality, then to get there you need 100 % process control. This was the perfection-driven pressure we were working under when it came to defining the nodal points of the impec frame.

We were looking for a solution that would pass all the requirements for the impec with flying colors in terms of weight, stiffness and quality. The frame joints placed particular demands on our engineers; indeed, the solution that we finally decided on would not have been recognizable as such when we first started on the development.

Construction, material and manufacturing process. These three aspects of the frame joints formed the Gordian knot of the impec which could not be untangled using conventional ideas. Everything seemed to be impossibly connected with each other. Until at some point we had the simple idea of creating the frame joints of the impec in two parts.

A clean cut then led to impec Technology no 2, the Shell Node Concept, where the joints at the nodal points of the frame are not one-piece collars but are each made from two half-shells. These half-shells are manufactured from a revolutionary composite compound material, are extremely rigid and yet light, have outstanding shock absorption qualities and can be connected to the frame tubes in the final assembly with absolute control and precision.

SNC - The Shell Node Concept process

impec Technology No 2 is the Shell Node Concept – SNC. With this extremely rigid and high precision half-shell technology, we can also design the frame joints of the impec so that there is nothing to stop us providing a lifetime guarantee..

SNC is the revolution in the construction of the impec. indeed, SNC allows us to design also the nodal points of the frame so that absolute process control is possible. Three aspects of the Shell Node Concept are of particular importance here. The design, the material and the process.

SNC is more than just a form of technology. SNC is also a design philosophy. The half-shell system allowed us to succeed in consistently transferring the technology of the BMC Skeleton Concept to the entire frame. The impec proudly wears its insides on the outside – it conceals nothing. However, key to the flawless quality of the impec are the inner qualities of the individual half-shells. Their ribbed structure defines the junctions to the frame tubes with absolute precision, while the inner and outer geometries of the shells are configured to optimize the load.

SNC was possible only through a new composite compound material which can be processed by injection molding and fully exploits the qualities of carbon as a material. The granules that are used consist for the most part of carbon fibers and a special 2-component resin.

Mold flow analysis
The direction of the carbon fibers inside the various shells can be precisely defined in a simulation process – mold flow analysis – before the final CAD data is fed into the tool construction program. With this mold flow analysis, our engineers were able to make the inside of the shell visible. in this way, we were able to record cleanly and continue to optimize all the key process parameters for injection molding, such as temperature, fill time, flow rate and flow properties.

Tests and CT
To verify the results of the mold flow analysis, the next stage involved construction of the injection molding tools. Small batches of shells were produced which we then subjected to a series of tests. This included scanning the half-shells in a computed tomography scanner. This is because CT allows us to conduct an accurate inspection of the wall thickness and check the overall structure for possible faults. Once these tests had also been successfully completely, nothing stood in the way of series production.

The marriage
In order to connect tubes and shells to the frame of the impec for extreme rigidity, the shells are first placed in a carrier system. This frame carrier is now fed into a robot workstation. The robot we use here is fitted with an optical monitoring system. It recognizes each individual component and defines the exact quantity and position of the composite adhesive to be applied.
And in order to meet quality requirements here as well, each contact point is monitored again before the tubes and shells are finally joined together for life. Firmly clamped into the carrier system, the completed frame is then cured in an oven and is then ready for the

Final quality control which is conducted using a static test process. The open design of the shell allowed for the fact that even the last stage of production of the impec frame – the bonding of the shells with the frame tubes – proceeded absolutely transparently in a controlled process.

the perfect finish

Even from its appearance, the impec looks different from all the rest. To ensure it remains flawless, its frame is assembled from guaranteed faultless components and requires no finishing. all components are individually finished and inspected and only then released for final assembly.

The digitally controlled paintshop where the shells and frame tubes of the impec receive their high gloss finish is absolutely state-of-the-art, and the lacquering of the impec is immaculate in meeting all environmental requirements and quality provisions. The enclosed system has a very efficient wet separation arrangement, generates little overspray and works with modern lacquers that are low in solvents. Providing the perfect finish is a “hollow wrist”, a particularly flexible hollow arm paint robot which lacquers the frame components of the impec in several layers using the wet-on-wet method. This process guarantees optimum adhesion between the individual layers of lacquer and therefore the best quality.

After the paintshop, the ways part once again for the half-shells and frame tubes. While the shells are only lacquered – it is their job to highlight the structural features of the frame – the frame tubes make their way to the printshop. Here they receive the final touch. Here the impec receives its branding.

First choice right from the start for the finishing graphics for the impec was the pad printing system. This print technology is the only process with fully automatic and industrial production capability for the printing of complex surfaces – such as the frame tubes of the impec. From a quality point of view, the result is comparable to lacquering. The pad printing system thus fits perfectly into the production philosophy of the impec. This process stands out from the rest in that the pads transfer the paint 100 % to the surface to be printed and the precise color printing is extremely resistant to environmental impact and scratches.

quality – from a to z

The quality we achieve with the impec is unique worldwide. it is the result of total control from the first to last stage of production. More than 60 different test parameters alone are recorded and analyzed in the manufacture of the frame tubes in the Load Specific Weave process. This results in carbon tubes that need no finishing and do not present voids or defects in the carbon structure.

This applies similarly to the production of the frame joints for the impec according to the Shell Node Concept, the lacquering of the tubes and shells, the printing and above all to the final assembly of the frame as well. Defective parts? negative. Guaranteed.

When the final stage of production is completed, each individual impec frame together with its fork is subjected to a static load test in where it has to hold its ground firm and true. The frame is subsequently measured and the report finally provides the informa- tion as to whether the frame meets the extreme quality requirements for the impec.

Random samples are also frequently taken from production which we subject to functionality tests and all have one thing in common: Even the strongest are tested to destruction. The aim of this controlled destruction is to obtain data about the maximum resilience of the impec which gives us information at the same time as to whether the entire process continues to achieve a zero-error rating. Absolutely rigorous, absolutely impec.