Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B19/00—Single-purpose machines or devices for particular grinding operations not covered by any other main group
  • B24B19/02—Single-purpose machines or devices for particular grinding operations not covered by any other main group for grinding grooves, e.g. on shafts, in casings, in tubes, homokinetic joint elements
  • B24B19/04—Single-purpose machines or devices for particular grinding operations not covered by any other main group for grinding grooves, e.g. on shafts, in casings, in tubes, homokinetic joint elements for fluting drill shanks
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B3/00—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools
  • B24B3/24—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of drills
  • B24B3/247—Supports for drills

Definitions

• the invention relates to a method and a device for grinding grooved tools, in particular helically grooved tools.
• the device described and the method described are suitable for producing helically grooved tools.
• the manufacture of twist drills is described in this description.
• grooved tools in particular twist drills
• a separate receiving sleeve is required for each tool diameter, which is matched to the nominal diameter of the tool to be manufactured.
• a lot of individually adapted accessories for the actual grinding machine are required for clamping and grinding the tools to be manufactured, which also means that when changing over to another tool to be produced, which has a different diameter, for example, in a variety of ways by exchange must be converted from parts.
• the tools to be manufactured may have different nominal diameters, there must be a separate receiving sleeve at least for each nominal tool diameter.
• the high retrofitting effort and the high number of specific accessories are associated with a high expenditure of time and high costs, which make the manufacturing process of the tools more expensive. Furthermore, from the use of sleeves in which the tools to be ground are guided, the problem of the insufficient accuracy of the guidance arises. Due to the system, the adjusted sleeve diameters have a play of 1 - 2 hundredths of a millimeter compared to the actual diameter of the tool to be manufactured. If, for example, the grinding wheel is grinded against the tool to be grinded when grinding the tool to be manufactured, this lies under the influence of the cutting forces in a punctiform or linear manner against the inside of the guide sleeve and is supported essentially only at one point on it Extent against the cutting forces. The guide is therefore not spatially fixed and depends on the geometry and the direction of the force applied by the grinding wheel to the workpiece to be ground. This leads to increased tolerances for the finished tool.
• the object of the present invention is to provide an apparatus and a method by means of which helically grooved tools to be ground can be produced in the same or less time in improved quality at a simultaneously lower cost.
• the object is achieved according to the invention with a device according to claim 1 and a method according to claim 16.
• the device according to the invention is used for grinding grooved
• the device for grinding grooved tools has a steady rest for guiding the tool to be ground.
• this bezel comprises a guideway with at least two inner side surfaces, each of which runs in planes essentially parallel to the longitudinal axis of the tool to be ground and enclose an angle for receiving the tool to be ground.
• the tool to be ground lies with at least two points on its circumference in each case against at least two of the inner side surfaces of the guideway, ie one of the at least two circumferential points lies against one of the at least two inner side surfaces.
• the tools to be ground can be tapered over their length, in particular slightly tapered.
• they can be conically tapered from their end face to their shaft.
• these essentially follow a weak taper of the tool, in which case they then run in planes essentially parallel to the longitudinal axis of the tool to be ground.
• the at least two side surfaces of the guideway run parallel.
• the course of the at least two inner side surfaces of the guideway can essentially follow the tool contour in longitudinal section, the planes of the side surfaces then being inclined in relation to one another, in some cases even differently over the length, in space.
• the inventive design of the device wherein the tool to be ground is guided in a guideway of a steady rest and rests at least on two circumferential points in this guideway, is one play-free storage and installation of the tool to be ground possible.
• the tool is guided in a sleeve and, viewed in cross section of the tool to be produced, lies only at one point on the side wall of the sleeve, as a result of which no reliable guidance can be achieved.
• At least two side faces of the guideway enclose an angle in which the tool to be ground is guided, and it is possible that, since the guideway in cross section with these side faces essentially widened, for example in a V-shape opens for receiving the tool, according to the invention tools with different diameters are ground.
• the tools are supported and guided on at least two side surfaces of this guideway, the respective contact point being able to lie at a different location depending on the work step carried out or the diameter of the tool to be ground, or a linear contact on at least two lines can be.
• the special construction for guiding the tool to be ground eliminates the need to use different guide sleeves depending on the diameter of the tool to be ground, and thus to have to hold many individual parts. Also, when changing to another tool to be ground, for example with a different diameter, the grinding machine does not necessarily have to be converted in a time-consuming manner.
• the tool to be ground is guided according to the invention at the at least two adjacent circumferential points in the guide path of the steady rest and is pressed against the side surfaces by the grinding forces, for example by a grinding wheel, which results in particularly good guidance since the grinding pressure over the at least two circumferential points affects the guideway.
• the direction of force of the grinding pressure is thus divided into partial forces in the direction of at least two circumferential points of the tool to be ground, in particular in the form of a parallelogram of forces, which is determined by the geometry and thus by the position of these points.
• the grinding device also has, in addition to the guideway, a tensioning lever which can be pivoted in the direction of the guideway in order to press or tension the tool to be ground. In this way, for example, in the face machining of grooved tools, in particular spiral-grooved twist drills, the tool to be ground is guided in a particularly safe and, in this case, play-free manner.
• the length of the guideway and, accordingly, the length of the tensioning lever correspond at least to the length of a slope of a groove helix of the tool to be ground. This is particularly advantageous since it ensures that there is essentially always at least part of the circular envelope of the tool to be ground for abutment with at least two circumferential points on the side surfaces.
• the steady rest including the guideway and the clamping lever, but also the guideway and / or the clamping lever, for use in the manufacture of extra-long tools, in particular twist drills, can be movable in the axial direction of the tool to be ground, so that it can be used in the area of the respective grinding work the tool to be ground always guarantee optimal support and guidance.
• the position of the steady rest and / or the guideway can also be set as a function of the diameter of the tool to be ground, the position of the longitudinal axis of the tool to be ground being predetermined and being different can result in particular from the geometry of the grinding machine used with the corresponding grinding units.
• This advantage is particularly preferably also given in that the guideway can be adapted as a function of the diameter of the tool to be ground.
• it can be advantageous to design the guideway for tools of larger or smaller diameter to be ground, in particular in the event of large jumps in diameter between individual tool batches to be produced.
• the guideway is preferably made of HSS (high-performance high-speed steel).
• the tension lever can also be made of HSS.
• the device it is advantageous to make at least the surface of the guideway and / or the surface of the clamping lever, in particular the part of the clamping lever which comes into contact with the workpiece to be ground in the event of being pressed on, from hard metal. It is e.g. possible to make this hard metal version in the form of strips which are attached to the corresponding surface of the guideway or the tensioning lever.
• the surface of the guideway and at least the surface of the clamping lever can also consist of polycrystalline diamond (PCD).
• PCD polycrystalline diamond
• the device can be provided for grinding tools made of HSS and / or for grinding tools made of hard metal.
• tools which are made from HSS corundum grinding wheels and / or CBN grinding wheels can preferably be used.
• diamond grinding wheels can preferably be used as the abrasive.
• the method for grinding according to the invention relates to the production of grooved tools which have an essentially circular envelope curve, in particular to the grinding of helically grooved tools by means of grinding wheels. Twist drills can be ground, but corresponding other tools, such as milling cutters, drills in general and possibly reamers, can also be ground.
• the tool to be ground is clamped according to the invention in such a way that a steady rest with a guide track with at least two inner side surfaces, each of which runs in planes essentially parallel to the longitudinal axis of the tool to be ground and an angle for receiving the include a grinding tool, in particular a steady rest with a guideway according to claim 1, the tool to be ground at least at two circumferential points, each of which abuts at least two of the inner side surfaces of the guideway, leads.
• the tool to be ground is pressed according to the invention by means of at least one grinding wheel when grinding the grooves into the guideway.
• a back of the tool to be ground is ground, it is preferred in this case also that the tool to be ground is pressed into the guideway during grinding.
• the tool to be ground is additionally pressed into the guideway with a clamping lever.
• Figure 1 is a plan view of a grinding machine with a device according to an embodiment of the invention.
• Figure 2 is a section on the line B-B of Figure 1;
• the grinding machine is made up of the following main groups: the machine stand 1, the grinding headstock 2 with swiveling grinding spindle unit 3 and with an HF grinding spindle 4, the grinding table 5 with a workpiece headstock 6, the steady rest with the guideway 8, and the dressing device 9.
• a grinding headstock 2 which can be moved by means of a CNC axis (X axis), is mounted on the machine stand 1 in the rear area. Furthermore, the height of the grinding spindle unit 3, which can be pivoted about an axis (A axis), can be moved vertically along an axis (Y axis).
• the grinding table 5 is built on guides (not shown), which can be moved in the direction of an axis (Z axis).
• the workpiece headstock 6, which is equipped with a collet head 61, is built up on the grinding table 5.
• the collet head 61 is accommodated on a quill which is driven in rotation about a CNC axis (C axis).
• the steady rest with the guideway 8 is constructed to support the tool to be ground on the grinding table 5.
• the dressing device 9 is arranged on the grinding table 5 with a rotationally driven diamond wheel 91 for dressing the grinding wheels used. All axes mentioned are designed as CNC axes.
• FIG. 2 shows a section along the line B-B of FIG. 1.
• the HF grinding spindle 4 is shown pivoted upward about 90 ° about the A axis, contrary to the illustration in FIG. 1.
• the X, Y and A axes are each drawn in and represented symbolically.
• the HF grinding spindle 4 is firmly connected to the swiveling grinding spindle unit 3.
• the grinding wheels 41, 42, 43 are accommodated in the front area of the HF grinding spindle 4, the HF grinding spindle 4 being designed such that both corundum, CBN or diamond grinding wheels are used can be included.
• CBN or corundum grinding wheels are predominantly used as abrasives.
• Diamond grinding wheels are preferably used for grinding hard metal (HM).
• the grinding table 5 In the front area of the machine stand 1, the grinding table 5 is shown, on which the steady rest is fastened with the guideway 8. To guide and support the tool 10 to be ground, this lies against the circumference of the guide track of the bezel 8. To grind end cutting edges, for example by means of a conical surface grinding, the clamping lever 83 is pivoted in the direction of the guideway in order to better guide the tool 10. To adjust the position depending on the diameter of the tool to be ground, the steady rest and / or the guideway can be manually adjusted in the direction of arrow 85.
• the structure of the device according to the invention, in particular the steady rest, with the guideway 8 is shown in cross section or in plan view from the end face of the tool to be ground, and the advantageous use of the device is illustrated by the method according to the invention using the example the grinding of twist drills explained in more detail.
• the structure of the bezel in the clamping area is shown in FIGS. 3 to 6.
• the tool 10 to be ground is a twist drill in the present case.
• the twist drill to be ground is in the workpiece headstock 6 by means of. a collet clamped at one end of the shaft. The clamping there serves only to transmit torque, the guidance is achieved through the bezel with the guideway.
• the shank of the tool 10 to be ground which projects freely from the collet is supported on the guideway 8.
• the tool 10 is supported via its free shaft length on the lateral surface 11 or the circumference of the essentially circular envelope curve on at least two circumferential points of the envelope of the tool 10 to be ground on at least white inner side surfaces of the guideway, which in the exemplary embodiment according to FIGS. 3 to 6 essentially has a prism shape as a cross section.
• the system at two circumferential points forms a “play-free” guidance of the tool 10 to be ground.
• the guideway can consist of HSS or can be equipped with hard metal strips or PCD strips.
• a clamping lever 83 is pivoted in this area, so that the tool to be ground between three circumferential points, seen in cross section in the form of a triangle around the Scope of the tool to be ground are arranged distributed, can be guided or clamped without play.
• Fig. 3 shows how a tool to be ground according to the invention is clamped and guided with its pivoted lever 83 over its shaft length.
• the linear systems are represented by points A1, A12 and A13.
• the radial rotation of the tool 10 to be ground takes place during machining through the C-axis of the workpiece headstock 6.
• the tool 10 to be ground is clamped by means of the collet 61. This must be exactly aligned with the guideway.
• the length of the guideway is determined by the length of the tool to be ground, the shape of the groove, the length of the groove and the pitch of the coiled grooves.
• the groove pitch has the influence that at least one complete groove helix must be covered by the length of the guideway.
• the frontal cutting edges of a twist drill can be ground, for example, in a conical surface by means of the grinding wheel 41.
• FIG. 6 shows the sharpening of the transverse cutting edge of the tool to be ground, in this case the twist drill 10, this working step being carried out with the grinding wheel 42.
• the machining is carried out on the end face or tip of the twist drill so that the clamping lever 83 is pivoted in again for clamping the tool to be ground.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
• Constituent Portions Of Griding Lathes, Driving, Sensing And Control (AREA)
• Grinding And Polishing Of Tertiary Curved Surfaces And Surfaces With Complex Shapes (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=7934342

Family Applications (1)

Country Status (7)

Families Citing this family (13)

Family Cites Families (15)

• 1999
  • 1999-12-23 DE DE19962796A patent/DE19962796A1/de not_active Withdrawn
• 2000
  • 2000-12-20 EP EP00990804A patent/EP1239995A1/de not_active Withdrawn
  • 2000-12-20 AU AU30150/01A patent/AU3015001A/en not_active Abandoned
  • 2000-12-20 US US10/168,667 patent/US20030060133A1/en not_active Abandoned
  • 2000-12-20 CZ CZ20022183A patent/CZ20022183A3/cs unknown
  • 2000-12-20 WO PCT/EP2000/013019 patent/WO2001047665A1/de not_active Ceased
  • 2000-12-20 JP JP2001548242A patent/JP2003518443A/ja active Pending

Non-Patent Citations (1)

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