WHAT IS FINE GRINDING?

• Fine grinding at Lapmaster Wolters is a batch-mode abrasive machining process that combines the speed and aggressiveness of super abrasive wheels with accuracy of lapping kinematics to produce flat and parallel work piece surfaces. 
• At double sided fine grinding, the fine grinding cutting tool consists of an upper and lower wheel composed of diamond or cubic boron nitride (CBN) with different bond types (vitrified bond, resin bond or metal bond) and act as the support plates for the work pieces. 
• The double-sided fine grinding machine has evolved from the vertical double-wheel lapping machine design with a planetary work drive system, also known as “lapping kinematics”. 
• In place of lapping wheels, grinding wheels are fitted and cooled through labyrinth in the working wheels and a coolant fed through holes in the upper wheel. 
• Since fine grinding requires higher forces and uses higher cutting speeds, motors, gears and the rigidity of the machines are much stronger than lapping machines. 
• Work pieces are guided between the upper and lower working wheel in an epicyclical path as defined by inner and outer pin ring, upper and lower working wheel, speeds and directions, while material removal takes place simultaneously on both sides.

• Accuracy results, previously only achieved by lapping 
• The pellet structure of the fine grinding wheel allows a layout of the fine grinding medium, corresponding to the kinematics conditions 
• Long and constant process cycles without dressing processes 
• The space between the pellets allows a high flow rate of the coolant 
• Very good chip flow without temperature problems 
• High process quality, consistent repeatability of achieved values 
• Also large surface work pieces can be machined 
• Fine grinding can use batch processing 
• Work pieces are loosely held in carriers and therefore machined stress free (without distortion - especially for machining of thin or delicate parts) 
• Work pieces of different shapes could be machined (i.e. round, rectangular or irregular; full surface or with cut-outs) 
• Easy to automate 

• High removal rate using super abrasive diamond and CBN (3 – 20 times faster than lapping) 
• Possible saving of pre-machining steps 
• Fine grinding benefits from long intervals between resharpening 
• Fine grinding has high flexibility 
• Automated solutions 

• Fine grinding benefits from the recycling of coolant 
• Tremendous less waste than with lapping 
• Minimal work piece cleaning necessary 
• Reduced downtime 
• Cleaning of work pieces without problems by rinsing; in comparison to lapping ultrasonic or chemical cleaning is not necessary 

• High removal rate (reduces capital costs and personnel expenditure) 
• Low wheel wear and long lifetime of the grinding wheels (reduces the tool costs) 
• Low waste disposal costs (reduces the current running costs) 
• Low work piece cleaning costs (reduces the current running costs) 
• Fine grinding may have a possible saving of additional machining steps 
• Easy grinding wheel maintenance 

• Performed with super abrasive (diamond or cubic boron nitride - CBN) grinding wheels 
• Stock removal caused by micro grooving / -cutting 
• Fine-ground surface has cross-hatched marks 
• Coolant is recycled 
• Fine-ground parts are coated only with a thin layer of coolant and therefore only minimal workpiece cleaning is necessary 
• Wheel speeds are typically 2 – 15 m/s 
•  3 – 20 times faster than lapping (removal rate) 

• Stock removal caused by rolling and sliding action of abrasive grains 
• Lapped surface is dull and crater-like 
• Material and lapping compound are not recycled 
• Lapped parts are contaminated with lapping compound and require cleaning 
• Lapping speeds are generally limited to < 1 m/s 

• Lapping flat parts (single or double-side) is the abrasive machining process for removing material using a loose abrasive in a liquid mixture (known as a slurry) at low speeds 
• Loose abrasive is moving over the surface under pressure and will knead, abrade, chip or scrape away the surface of the workpiece. By exceeding the bending strength the material breaks out. 
• Fine Grinding (flat parts – single or double-side) is the abrasive machining process for removing material using a bonded Superabrasive wheel at low speed with a liquid to keep the part cool. The fixed grain of a geometrically indefinable cutting shape acts like a plow and material is removed by micro-grooving /-cutting. The chip formation occurs by exceeding the shearing strength. 

Lapmaster Wolters offers a complete line of products for all fine grinding requirements. This ranges from equipment for low-volume job shop applications to fully integrated systems for high-volume fine grinding for industrial production applications. Additionally, Lapmaster Wolters also offers used fine grinding (rebuilt and refurbished) and upgrade services for existing fine grinding machines. We provide you with fully engineered complete custom solutions and offer a full line of accessories and consumables in addition to comprehensive training and repair services. 

To match your requirements, our fine grinding machines can be made to be manually operated or fully automated.