Long before Levicron was founded by Dr. Ralf Dupont it was clear to him that because of the required part precision this business could not be built up based on suppliers and sub-contracted work. Thus a vertical business integration including bespoke machining and process development, shaft and bearing parts in particular, was part of his business plan right from the beginning.
Therefore not only 97% of the parts and components of their products are developped, manufactured and tested in house, but also the entire service work, customer support and process development with and for our products to support our customers before and after purchasing comes from Levicron.
Hence our Slogan: Ultra-Precision meets industrial Grade
Calculating and simulating bearing characteristics and shaft dynamics is only half the way you need to go to reach your destination. But to use analytics, FE Analysis and CFD Analysis to optimize the later product performance is way more important to provide your customer with the optimal spindle solution for his application. Thus in Levicron bespoke anlytical methods and FE simulation tools are combined in closed loop optimization cycles based on genetic and popolation based algorithms. With the shaft, bearing and jet geometries as input variables they deliver their optimal sizes after a multi-objective optimization cycle. The multi-dimensional objective and solution space can be defined to any application, wheter it is robustness, optimal dynamics or the best compromise. This process is affected by issues like thy are known for natural genetic coding … information degenration, tail degeneration or elitism.
For spindle prodcuts from Levicron the following anytical and numerical development tools are used:
- Analytical methods for the performance description of non-contact bearing systems
- FE Structural Analysis for the prediction of centrifugal load or temperatur caused deformation
- Numerical Fluid Dynamics to predict the flow characteristics and the local thermal conductivity of bearing gaps and cooling jackets
- Open loop optimzation (1-way FSI) of Analytical, CFD and FE Analysis to predict deformations and their influence on bearing performance and shaft dynamics
- Closed loop evolutionary, analytical optimzation for bearing and shaft geometries based on weighted functions to get optimal bearing performance and shaft dynamics
- 3D CAD/CAM for production parts modeling
- CAD/CAM for productiong drafting
The manufacture of one of our spindle shafts require more than 20 single manufacturing steps where every step that needs to be matched to the previsous one. It is obvious that finish drawing is not useful.
After the creation of a 3D model of each part of a spindle assembly and the final spindle assembly model production models are derived. These include dimensions and allowance for the next machining step. These production models now allow the derivation of station drawings that define dimensions, shape and position tolerances and the allowance for each machining step.
Even for complex spindle components that require many production steps their manucaturing process can be realiably controlled.
Even before setting up a business plan for Levicron it was clear that for the manufacture of ultra-precision spindles production technology and internal manufacturing will be a very part of the success. Together with his sound knowledge of manufacturing techniques – Grinding, Diamond-Turning and Laser-Drilling in particular – Dr. Ralf Dupont was aware of that for the required part precision no sub-contractor can be used. The result of trying sub-contractors for standard turning and milling work at the beginning confirmed his thoughts. Part quality and the reliability of the suppliers used didn’t comply with what was needed.
As a result Levicron vertically integrates 90% of the production technologies required to manufacture ultra-precision motor spindles and can now not only offer bespoke solutions to their customers, but also a very quick customer support and turn-around time. Production Technologies developped and used in Levicron include:
- CNC Turning (with and without life tooling)
- CNC Milling (3 and 4 Axis Machining)
- CNC Cylindrical Grinding
- CNC Bore Grinding
- CNC Diamond Turning
- Flat Grinding
This includes besoke machining solutions which contribute to the precisio and quality of Levicron Spindle Products.
An error or mistake during the manufacturing process often can be seen during testing, but the way of the affected part (s) in between can be long and can cause financial losses and a tremendous loss in time. Thus all parts and assemblies are measured and tested in accordance with the corresponding station drawing.
While dimensions and diameters often can reliably be checked with gauges or micrometers shape – like cylindricity – and orientation – like squareness – require CNC form measurement. CMM’s and Form Testers are part of our inspection to ensure part quality.
Measurements of each part are recorded and stored in protocols to keep track of single parts in differnt batches. For this production and inspection control is essential and is done with our MRP system.
The modular design of our spindle products allows to assmeble, test and store sub-assemblies which then can be used to assemble and test the final product in very short time. Thus we store bearing cartridges, spindle bodies and flange units to be ready for your order at any time.
To get to this point much development and optimization work was necessary. As a results turn-over and lead time are much shorter than with any other spindle manufacturer.
Before a spindle is build from the modules all sub-assemblies are tested by different performance and accuracy tests. For example bearing system, tool clamping, spindle encoder and motor are tested before a bearing cartridge goes to stores. For final testing our spindle products get tested with different static and dynamic short and long-term tests. These include:
- Tool change cycling and final tool clamp approval
- Static radial and axial load capacity tests
- Determination of the axial and radial concentric static spindle stiffness
- Multi-step coolant jacket leak-down tests
- Dynamic testing with drive data recording
- Motor stress tests
- Dynamic run-out and vibration recodring with speed
- Spindle Error-Motion verification
- Long-term spindle run with final approval
For the dynamic behaviour and ultra-precision at high speed dynamic balancing is not only curcial, to get spindle qualities we promise our customers dynamic balancing is Levicrons speciality. Our tool spindles leave our premises with a balance quality of better G0.05 mm/s at 60.000 rpm measured in three planes. It’s obvious that for dynamic balancing to such values no commercially available can be used. Thus Levicron developped unique and bespoke balancing rigs for their spindle and tool holder products.
This also applied to our HSK tool holder series UTS-x. While the industry standard specifies G2.5 mm/s at 25.000 rpm Levicron sells their tool holders with G0.3 at 60.000 rpm and are thus 20 times better with respect to balancing than the industry standard DIN69893. The residual imbalance and even the tool clamp repeatability can be measured and verified by our 4×90° reversal test. For our tool spindles AS-H25 and ASD-H25A we specifiy a tool clamp repeatability of better 0.2 micron if used with our HSK tool holders UTS-x that comply with DIN69893.
Our aerostatic spindle solutions comply with the current standard for CNC tool spindles. This includes the spindle encoder, the liquid cooling, the synchronous motor and the tool change. However the end customer and the machine builder can save much time by making use of our sound knowledge of setting up, optimizing and running our spindles.
With our Spindle Retro-Fit and Intefration Kits we offer this service for any common machine control and spindle drive. Get more information on our Retro-Fit and Integration Kit page.
The same applies for a service case. Together with a motivated team of skilled engineers we support you quicker than you would expect.