Our stock of machine tools for sale : CNC jig grinding machine

A jig grinder uses a small abrasive wheel driven by a high-speed spindle to remove material from a workpiece. The movement of the grinding wheel and the workpiece is controlled by a CNC system, which allows complex three-dimensional paths to be created. The machine's axes (X axis, Y axis and Z axis) are controlled with high precision (to the micron), enabling complex geometric shapes to be obtained, ranging from flat surfaces to free-form shapes, and high-quality surface finishes.

Jig grinding machines are extremely precise, allowing dimensional tolerances in the micrometre and even submicrometre range (Ra < 0.01 µm), depending on the machine configuration, the tools used, the grinding wheel material, and so on. At the same time, they guarantee high quality finishes, with very smooth, shiny surfaces and roughness down to a few nanometres.

The addition of digital programming technology (CNC) to the intrinsic precision of coordinate grinders gives these machine tools a high degree of repeatability for machined parts. This feature is essential for meeting the particularly high quality requirements of the cutting-edge industries that use this type of machining. It also reduces the waste of potentially expensive materials such as superalloys, titanium, rare metals and certain composites.

These machine tools are also extremely versatile, capable of grinding a wide variety of materials, from hard metals to ceramics and composites. So, although they are seen as complementary to traditional forming machine tools, such as drills or milling machines, CNC coordinate grinders stand out in applications requiring extreme precision and impeccable surface quality. Their ability to produce complex geometric shapes with micrometric tolerances makes them particularly well suited to specific tasks.

The grinding wheel

The jig grinder's main tool is its abrasive wheel, made up of abrasive grains (diamond, CBN, aluminium oxide, silicon carbide) bonded by a binder (vitrified, resin, metal). The grinding wheel can be of different shapes (disc, cup, roller), diameters and profiles (flat, conical, profiled) to adapt to the complex geometries of the parts to be machined. Wheels wear during machining due to abrasion and grain fragmentation. They therefore need to be dressed or replaced regularly to maintain optimum grinding quality.

The wheel spindle

This rotates the grinding wheel at very high speed, generally several thousand revolutions per minute (RPM). A distinction is made between direct-drive and indirect-drive spindles. Direct-drive spindles are coupled to the motor and are more rigid and precise, but also more expensive. The precision of the spindle rotation is a determining factor in the quality of the ground surface, as vibrations and imbalances can lead to surface defects.

Essential systems: cooling, lubrication and filtration

• The cooling system evacuates the heat generated by grinding and prevents surface deformation and alteration of the crystalline structure of materials caused by overheating of the workpiece or the grinding wheel.
• The lubrication system, which lubricates the machine's mechanical components to reduce friction and wear.
• The filtration and suction system, which removes wear particles and debris from the cutting oil. Debris can be extremely damaging to the machine, the grinding wheel and the workpiece, so it must be removed as quickly and efficiently as possible.

Coordinate grinders such as the HAUSER S40-400, a high-precision CNC jig grinder, are indispensable tools for meeting the production needs of many industries, particularly those requiring extreme precision, flexibility and unrivalled surface quality.

The aerospace industry, where every gram counts and reliability is paramount, uses jig grinders to manufacture complex, precision parts such as engine spindles and high-precision moulds for composites. These parts require an impeccable surface finish and extremely tight tolerances, which only these machines can guarantee. Their ability to machine demanding materials such as light alloys (aluminium, titanium) with precision reinforces their importance in this demanding sector.

In the automotive industry, mass production of high-precision parts is essential. Coordinate jig grinders are used to manufacture engine components such as crankshafts and cams, as well as moulds for plastic parts, ensuring optimum performance and extended vehicle life.

The medical sector demands extremely high standards of quality and precision. Coordinate jig grinders are used to manufacture dental implants, surgical instruments and prosthetic moulds. Their ability to work materials such as titanium, stainless steels and medical ceramics while maintaining impeccable surface quality is crucial to ensuring the safety and effectiveness of these medical devices.

Watchmaking, where miniaturisation and precision are essential, is the historical home of these machines, such as the famous Swiss brand of jig grinders Hauser, which developed them to meet the specific needs of this industry. The watchmaking industry takes advantage of the capabilities of jig grinders to manufacture watch components such as cases, bracelets, plates and internal mechanisms. These machines provide meticulous finishes and extremely precise dimensions, contributing to the quality and aesthetics of watches.

The moulding industry uses jig grinders to manufacture high-precision moulds for plastic injection, stamping and die-casting. These moulds can be used to produce parts with complex shapes and smooth surfaces, meeting the requirements of many industrial sectors.

Widely appreciated for their many advantages, CNC coordinate grinding machines play a key role in precision machining workshops. Their integration is a significant driver for improving quality, repeatability and machining accuracy. However, acquiring such a machine tool represents a investment for companies in the sector. This is why many players in precision machining turn to the used machinery market to acquire their CNC coordinate grinding machines.

Kraffter Machine Tools has specialised in the refurbishment, restoration and retrofitting of machine tools, including CNC jig grinders, in order to offer a less expensive alternative to this problem and enable everyone to acquire a reliable means of production. The complete refurbishment of a CNC jig grinder allows you to acquire a solution equivalent to the original machines without having to pay the full price.

We carry out a complete diagnostic of each jig grinder as soon as it arrives in our workshop, followed by a thorough cleaning of the machine and its peripherals.

We then carry out a complete overhaul of the machine, covering mechanical, hydraulic, pneumatic and electrical aspects.

If necessary, we use our own machine tools to remanufacture the parts for the overhaul. We also replace components such as ball screws, linear guides, axis drives, spindles, mechanical wear parts, electronic components, etc., as required.

Each machine is delivered with a geometric inspection report, certifying that its performance complies with the manufacturer's original specifications. Finally, on request, we can take care of all the logistics, including customs formalities, transport and handling of your machine.

Buying a used jig grinder can be a cost-effective option, provided you carry out a rigorous assessment of its condition. This requires specific expertise to analyse the machine in detail, taking into account the operations to be carried out and its general condition.

The hidden risks of buying a second-hand jig grinder

Second-hand machine tools on the market often have :

• Unnoticed technical problems (alarms, malfunctions).
• Misaligned or maladjusted axes, resulting in a geometry that does not comply with the manufacturer's original tolerances.
• Damaged slides or linear guides, compromising their precision and performance.
• A worn or unbalanced spindle, causing excessive vibration and poor finish quality.

In these situations, it will be necessary to call in a specialist technician to carry out the necessary readjustments. However, this can lead to :

• Longer intervention times, often due to the technician's unavailability.
• High additional repair costs, cancelling out the initial savings made at the time of purchase.
• Unplanned machine downtime, resulting in lost production and missed opportunities.
• Increased customer dissatisfaction due to delays in your production lead times.
• Difficulty in obtaining spare parts, as specific parts can be rare or hard to find.

To avoid these inconveniences, it is essential to choose a reconditioning specialist like Kraffter Machine Tools. We ensure that every used jig grinder goes through a rigorous process of overhaul, verification, restoration and repair, guaranteeing that it is in good working order. What's more, every one of our machines can be seen live for demonstration purposes, ensuring total transparency. Thanks to our expertise, you can eliminate the uncertainties associated with the condition of the machine and avoid unpleasant surprises.

Advice on buying a used machine tool

Visual inspection, a key part of the evaluation: Visually inspect the general condition of the machine (a clean, well-maintained machine is a reliable indicator of its working order), check the geometry, the play of the mechanical components and the operation of the lubrication, cooling and filtration systems. This is useful for detecting premature wear in one or more components.

Ask for the machine'stechnical documentation (user manual, electrical diagrams, hydraulic and pneumatic diagrams, etc.) to make it easier for the operator to get to grips with and maintain the machine.

On-site trial: Make sure the machine can be seen powered up before making your decision. If possible, attend a demonstration to check its operation and precision and avoid any unpleasant surprises.

Kraffter Machine Tools can take over your second-hand jig grinders. If you wish to sell your unused jig grinder or replace a machine, our expertise guarantees you a fast trade-in adapted to industrial requirements.

Why trust us to buy back your jig grinder?

• Transparent trade-in: A fair offer based on the condition and potential of your jig grinder, whether it's operational or broken down.
• Rapid response: Evaluation of the machine and quotation within 24 hours.
• Purchase for our own stock: Machines are bought back, reconditioned and integrated into our fleet.
• Turnkey service: We take care of dismantling, handling and transport.
• Recovering used machines: Recover your unused equipment and take part in the circular economy.

With Kraffter Machine Tools, selling your used jig grinder is simple, quick and efficient. Contact us now for a detailed estimate tailored to your needs.

Kraffter is a company specialising in the purchase, reconditioning and retrofitting of second-hand machine tools from leading brands such as HAUSER and MOORE TOOLS.

Discover all of our high quality second-hand grinding machines of all brands (KELLENBERGER, etc)