The mechanical properties of the engraving machine
and the factors affecting the engraving
1. Mechanical properties of engraving machine
include flatness, perpendicularity, positioning accuracy and repeatable positioning accuracy, etc.
Flatness mainly affects the leveling difficulty of plates and workpieces.The perpendicularity between axes mainly affects the dimensional accuracy of the workpiece. When the perpendicularity between the XY axis is large, the typical manifestation is that the diagonal of the rectangle is not equal. When the perpendicularity between the Z axis and the XY plane is large, the typical manifestation is that the surface is uneven when the plane is milling with a flat bottom knife with a large spacing.The positioning accuracy affects the size error of the workpiece, which mainly depends on the precision of the screw, the compensation ability of the control system and the change of the ambient temperature.When the machining range exceeds 300 mm, the effect of positioning accuracy on workpiece size must be considered.Repetitive positioning accuracy mainly affects multi-tool machining and multi-process machining.Engraving machine adopts roller screw drive, no crawling phenomenon, can achieve micro feed repeat positioning accuracy mainly depends on the control accuracy, generally 2 control resolution.
2. Environmental factors that affect sculpture mainly include power supply, vibration, ambient temperature and humidity, dust, lightning, etc.
The influence of power supply on machining is the most direct, mainly manifested as control system disorder.Each electronic device and each functional part of CNC control system has a certain range of voltage and frequency.The overload operation of any component will inevitably lead to the instability of the whole system. The common phenomenon is machining deviation.The effect of vibration is reflected in the frequency of short knives and the surface is not smooth.Common reasons are the process of contact machine tools, machine tool installation level is not qualified, there is a punch around.Ambient temperature and humidity mainly affect the performance of the control system and the performance of the driving motor.When the ambient temperature exceeds 40 degrees, the control system may have incorrect control and the driving torque of the drive motor may not reach the rated value.Dust mainly affects the heat dissipation of electronic components and the sensitivity of photosensitive components.Common phenomena include the failure of light detection of the CPU fans of the computer and so on.
3. The main factors that affect the engraving properties of materials are the types, hardness and toughness of materials.The categories of materials include metallic and non-metallic materials.In general, the higher the hardness, the worse the processing, the greater the viscosity, the worse the processing.The more impurities, the worse the processing, the higher the hardness of the particles inside the material, the worse the processing.A general standard is: the higher the carbon content, processability, the worse the higher alloy content, workability, non-metallic element content is higher, the better processability (but the amount of non-metallic in general materials is strictly control) is suitable for the nonmetal materials including carving, wood, organic glass, resin, etc., are not suitable for engraving of non-metallic materials including natural marble, glass, etc.Suitable for carving metal materials include copper, aluminum, hardness less than HRC40 mild steel, not suitable for carving metal materials include hardened steel, etc.
4, the cutting tool factors that affect the engraving processing include the cutting tool material, geometric parameters, grinding technology.The cutting tool material used in engraving is carbide, which is a kind of powder alloy. The main performance index that determines the material performance is the average diameter of the powder.The smaller the diameter, the more wear-resistant the tool, the more durable the tool.The sharpness of a tool mainly affects the cutting force.The sharper the tool, the smaller the cutting force, the smoother the machining, the higher the surface quality, but the lower the durability of the tool.Therefore, different sharpness should be chosen when processing different materials.The processing of soft and sticky materials, the need for some sharp tools, when the processing material hardness is larger, to reduce the sharpness, improve the durability of the tool.But not too blunt, otherwise the cutting force will be too large, affect the processing.The key factor in tool grinding is the mesh of the finishing wheel.The grinding wheel with high mesh number can produce finer cutting edge, which can effectively improve the durability of the tool.The grinding wheel with high mesh number can produce a smoother cutter surface and improve the cutting surface quality.
tool installation is a very important work, if the tool is not installed correctly, not only will increase the tool wear, but also cause accuracy is not accurate, to the processing of difficult, so must cause enough attention.The following methods for the correct installation of engraving machine tools are summarized:
1. Before the tool is installed, the wear condition of the knife should be checked first. If there is a broken blade, serious wear and other defects, replace the new knife or use it after it is repaired.
2, the surface must be cleaned and wiped clean before installation, carefully remove the washer and orifice burrs, prevent dirt and burrs affect the precision of tool installation position.
3. When the tool is clamped with a washer, the two end faces of the washer must be as parallel as possible.If the milling cutter is found to be askew after installation, the washer position should be adjusted to minimize the accumulated error of the washer.Until the rear milling cutter does not shake.
4, taper shank milling cutter installation, milling cutter, middle sleeve, spindle between the taper must be consistent, try to make the installation center and tool center concentric.
5. After the shank is inserted into the spindle, use the tension screw to tighten the milling cutter.It should be noted that the milling cutter must be rotated in the same direction as the thread of the pull rod in order to make the pull rod thread more tightly connected to the cutter in the rotation, otherwise there is a risk that the cutter will come out.
6. Make the milling cutter close to the spindle bearing and the hanger bearing close to the milling cutter as far as possible without affecting the processing.If the milling cutter is far from the main bearing, a hanger bearing should be installed between the spindle bearing and the milling cutter.
7, when installing the milling cutter, should not remove the key.Because there is no key on the cutter shaft, if the milling force is not uniform or in the case of heavy load cutting, the cutter often slide, then the cutter shaft itself bears a lot of radial resistance and resistance, easy to make the cutter shaft bending and damage the fixed washer
8. After the milling cutter is installed, check all the relevant washers and nuts again to prevent looseness.Use dial gauge to check the diameter jump or end jump of the milling cutter to see if it is within the allowed range.
9. After the knife shaft is removed, it should be hung on the shelf to prevent the knife shaft from bending and deformation.Under special circumstances, when horizontal storage is needed, wood chips or other soft goods should be placed well to prevent scratch and deformation.