磨具硬度是指在磨削加工时，磨粒从磨具表面脱落的难易程度

1．  在一般情况下，硬度较软的砂轮用来磨削较硬的工件,硬度较硬的砂轮用来磨削较软的工件。

2．  磨削时，工件与磨具的接触面大或进给量大时，应把磨具硬度选软些。成型磨削时，为保证工件几何形状的精度，可适当提高磨具的硬度。

3．  磨削导热性能差的工件的刃磨刀具，为避免烧伤、退火，磨具硬度应选软些。

4．  高速磨削时，磨具硬度应选软些；干磨比湿磨用的磨具硬度也应软一些

The hardness of abrasive tools indicates the difficulty of abrasive grains falling off the surface of the abrasive tools in cutting.

1.       Generally, the grinding wheels in soft hardness are used for cutting harder workpieces, whereas the wheels in a bit higher hardness are used for cutting soft wokpieces.

2.       In the process of cutting, if the wokpieces is touched greatly of the feeding is large, it is available to select soft hardness. For forming-grinding, it is better to select the wheels in higher hardness to guarantee precision of the workpieces.d

3.       when grinding the workpieces with weak capcacity of heat-transmission and cutting tools, it is better to select softer hardness to avoid burning and annealing.

4.       When grinding at high speed, it is better to select to select softer hardness; The hardness in dry grinding should be softer than that in wet grinding.

结合剂是将磨粒粘结成各种形状磨具的材料。常用的磨具结合剂有陶瓷和树脂两大类。

Bond is the material for adhering the grains into various shapes. The common bonds fall into two catalogues.

组织号是指磨粒体积占磨具体积的百分率。磨粒所占的比例越大，组织就越紧密，反之就疏松。组织疏松（磨粒率低）的磨具，磨粒间的气孔多，排屑方便，工件散热性好，不烧伤。组强紧密（磨粒率高）的磨具，能保持较好的几何形状，被磨工件的表面粗糙度好，加工精度高。

 Structure no is the percentage fo the grain volume in the volume of abrasive tools. The bigger the grains’percentage is, the structure is. Otherwise, the structure is porous. The abrasive tools in the porous structure are characterized by more holes among grains and easily-removing metal fillings, and excellent capacity of heat-radiating and burning no workpieces. The abrasive tools in dense structure feature well-kept shapes and high cleanness of the workpieces and high grinding efficiency.

磨具按形状、尺寸、磨料、粒度、硬度、组织号、结合剂、线速度顺序书写

磨具的保管

1．             使用单位收到磨具后，应仔细检查是否有裂纹及其他损伤，并认真核对磨具表面有关商标标专是否正确、清晰、齐全。

2．             磨具在搬运时应小心轻放，防止振动和碰撞，并禁止在地上滚动。

3．             磨具存放时应防止受潮、受冻、室温不应低于5℃

4．             树脂磨具不能与碱类物质接触，以免降低硬度和强度，存放时间超过一年者，应重新进行回转强度检验后，方可使用。

 砂轮的正确安装

1．  安装前应仔细检查砂轮是否有裂纹，并用木棰敲击砂轮，听其是否有哑声。若发现有裂纹和哑声，严禁安装使用。

2．  校对机床主轴转速是否与砂轮端面标明的最高安全使用速度相符。

3．  在安装砂轮时，应使用卡盘紧固，两卡盘的外径尺寸必须相等。两卡盘与砂轮端面之间，应放上弹性材料制成的厚度为1-1.5毫米的石棉垫，橡胶板或纸板等。并在卡盘圆周外伸露1毫米以上。

4．  外径为150毫米及以上的砂轮，装上卡盘后应先进行静平衡，再安装到磨庆上进行修整，修整后应再次进行平衡方可使用。

5．  砂轮孔径与机床主轴（或轴套）的配合松紧要适当，间隙不易过大

6．  紧固砂轮时，只允许使用专用手动螺母扳手，严禁使用补充夹具或敲打工具，如有多个压紧螺钉时，应按对角顺序旋紧，旋紧力要均匀。紧固时，应注意螺母或螺钉的松紧程度，压紧到足以带动砂轮并不产生滑动的程度为宜，防止压紧力过大造成旋涡破损。

      砂轮的安全使用

1．  在开动机床前，应检查机床的防护装置及各种运作的复位开关是否调整到位且牢固。

2．  使用的防护罩，应至少罩住砂轮直径的一半。

3．  砂轮安装于磨床主轴后，必须进行空转，空转时间不少于5分钟

4．  不是专门使用端面工作的砂轮，禁止使用砂轮端面进行磨削

5．  在进行磨削加工时，禁止使用杠杆推压工件来增加对砂轮的压力。

6．  磨削加工或修整砂轮时，吃刀量要适当，并使用专门修整工具修整砂轮。

7．  禁止使用对磨具结合剂有破坏性的磨削液。

 Storage:

1.       when receiving grinding wheels, users must carefully check whether there are cracks or other damage. It is necessary to check the brandmark is correct, clear and complete.

2.       the wheels must be handed with care and kept from colliding and vibrating. It is prohibited to roll the wheels on the ground,

3.       Grinding wheels must be stored in a dry place and be kept from humid and being frozen. The storing temperature can not be less than 5℃.

4.       Resin-bonded wheels must be kept away fromalkli materials in order to maintain the hardness and strength. The wheels stroed more than one year can be used only after its strength proves to be qualified by revolving test.

Installation:

1.     Grinding wheels can be installed only after careful test which proves there are no cracks or abnormal sounds ( which can be heard by tappin them with a wood hammer. It is prohibited to use the unqualified ones.)

2.       Adjust the revolving speed of the axle of lathes and make sure it complies with the max speed marked on the grinding wheels.

3.       When the wheels are being installed, it is a must to fasten them with chucks.The diameters of the chucks must be equal. Asbestos washers, rubber boards or cardboards in thickness 1-1.5mm must be fixed between the chuck and the surface of grinding wheels. It is required to extend at least 1mm of washer or boards around the outside of the chucks.

4.       Regarding the sheels with diameters more than 150mm,fix them with chucks and test its static balance. Then install the wheels to the grinder for adjustment. After adjusting the wheels, test the balance again.

5.       the hole and the axle of the lathe(xale sleeve)should fit well, and the rift should not be too big.

6.       When fixing grinding wheels, only special nut wrenches can be used. It is prohibited to use clamps of tapping tools, If there are many nuts, the nuts should be fastened diagonally, the fastening force should be even. When the wheels are fixed, close attention should be paid to the tightness of the nuts or bolts, it is available to fix the bolts just till the wheel can revolve without any slide so that the breakage of the wheel under high pressure can be avoided.

Usage: 

1.     Before starting the lathe,check the protection cover and the switches for various actions to observe whether they can be adjusted to the place where they should reach and whether they have been fixed well.

2.       The protection cover should cover at least half of the wheels

3.       After the wheels are installed onto the main axle of the althe, they should race for at least 5 minutes.

4.       The surface on both sides of the grinding wheels can not be used for grinding unless the wheels are made on the purpose.

5.       When in used, it is prohibited to push the workpiece with lever to increase pressure on grinding wheels.

6.       when processing or repairing the grinding wheels, penetrate the cutting fool properly. Repair and maintain grinding wheels with special toos.

7.       Close cooling liquids before the wheels stop to avoid bad influence on the static balance.

8.       It is prohibited to use grinding liquids destructive to the bonds of grinding wheels.