Mold plating before the preparatory work
In order to ensure the quality of plating, molds should be checked and prepared before plating, first of all, the mold polishing treatment, the general use of tools include:
(1) sandpaper: for coarse polishing, remove surface burrs and scratches.
(2) oil stone: used for fine polishing, to further improve the surface roughness.
(3) Polishing cloth: used to polish the details and edges of the surface.
(4) Polishing liquid: used to moisten the polishing cloth and improve the polishing effect.
(5) Polishing machine: used to drive the polishing tool to improve the polishing efficiency. Different mold materials and shapes require different polishing tools and methods to ensure that the mold profile is clean before plating. In addition, the locator needs to be removed in advance in order to avoid damage to the mold during transfer and plating. The unloading top bar of some molds should also be removed to prevent plating solution from being left in the holes.
Mold locator and top bar removal before plating the mold surface inspection to ensure that the surface is smooth and flat without defects, if there are cracks, sand holes, air holes and other defects, the defects of the surfacing and grinding leveling treatment to ensure that the mold in the plating of the surface quality before the problem-free.
Defect identification and treatment of plating process in order to ensure the quality of plating, should be strictly in accordance with the following process:
Mold plating process flow chart
(1) Mold surface inspection, confirm the mold surface state, plating area measurement;
(2) Mold cleaning, remove mold surface oil, debris;
(3) Mold surface with grinding tools for grinding, grinding, removal of mold surface oxide layer;
(4) Isolating and masking the places that do not need plating;
(5) Mold chrome plating surface for anode design, the process is a more complex, time-consuming work, but also more about experience and skills, directly affecting the quality of chrome plating;
(6) The mold is placed on the bracket, and the mold and bracket are placed together inside the plating tank for plating, and the plating temperature is about 55℃. According to the area of the mold plating, the mold material is different, whether the mold has been surface burnishing, set different current parameters, need experience and skill;
(7) After plating, remove the mold, anode, fixture disintegration;
(8) Put the mold into the neutralization tank (alkaline liquid);
(9) Remove the mold, use high-pressure water to clean the mold, and use compressed air to blow dry the liquid left on the mold;
(10) After the completion of the mold surface grinding, remove the mold plating surface burrs, so that the mold plating surface is flat and smooth. Sandpaper first with 320, and then 800 sandpaper for grinding, and finally check whether the surface quality of the chrome plating layer is qualified.
Mold plating after the production of verification work mold plating work is completed, before production needs to do the following verification work:
Mold plating quality inspection
(1) Mold plating overall quality inspection: pay attention to the molds that have been patched or the stress relief is not sufficient for the new casting molds in the plating process may produce cracks, or the original cracks to expand and other defects, as well as mold air holes, sand holes, cracks, and other factors that produce problems.
(2) mold plating thickness detection: mold plating process by the lead wire placement, mold surface roughness and other factors, there is uneven plating thickness, should be more points to detect the mold away from the R angle and mold profile.
(3) mold plating surface roughness detection: check the stretching mold concave mold, convex model surface plating surface roughness shall not be higher than Ra4μm, should focus on the surface of the R corner of the walk material and other key parts, to reduce the friction of the sheet walking process, reduce the wear of the plating layer.
Overall quality inspection of the mold
(1) Mold outside the surface of the paint quality check: check whether the paint color is correct, whether the paint is completely solidified, the paint surface should not be peeling, granular condensation and so on.
(2) mold plating liquid residue inspection and cleaning: mold back cavity, exhaust holes are easy to residual plating liquid, plating liquid is highly corrosive, should ensure that the plating liquid on the mold clean before production.
(3) mold parts installation surface inspection and cleaning: check the mold parts safety surface without paint foreign matter, to ensure that the mold parts back to install the positional accuracy does not change.
Parts production quality verification
(1) stretch forming mold: in order to control the production variation point, for stretch forming mold before and after plating, plate performance parameters (focusing on the yield strength of the plate) should be in the normal range, it is recommended to retain the mold plating before the cold die production of stretching parts, used for plating with the cold die production of stretching parts after the amount of plate inflow comparison, such as the emergence of problems can be used as a basis for determining the quality of the variation. In addition to comparing the inflow of cold mold drawn parts before and after plating, the parts of the type surface and the R angle of the material to be checked for quality.
(2) flanging shaping knife block: before and after plating parts flanging shaping quality inspection, including flanging gap, shaping pressure wound inspection and parts flanging rectification quality inspection.
Mold plating after the chromium layer process maintenance and maintenance of mold chromium layer maintenance notes
(1) The plating layer should not be bumped or crushed;
(2) The surface of plating layer must not be coated with corrosive substances;
(3) The dust in the stamping workshop has a great influence on the chromium layer, and it should be prohibited to carry out fire and grinding operations near the mold storage area, and the mold should be checked and confirmed before closing;
(4) Plating after parts forming process folds will shorten the life of the plating, should reduce the problem of parts folds, focus on and timely adjustment.
Routine maintenance
(1) Establish the plating life account of each model of mold concave mold, convex mold, crimping ring, flanging cutter block, shaping cutter block, according to the scheduling situation by monthly or quarterly update of the account, as one of the bases of the mold plating plan.
(2) mold plating life cycle, according to the depth of the mold stretching mold will be divided into deep stretching molds and shallow stretching molds, and combined with the workshop mold PM plan, the establishment of mold plating layer inspection plan, the use of plating thickness gauge multi-point detection of the mold plating thickness and record analysis.
(3) daily drawing model surface maintenance should be through the maintenance personnel visual, touch inspection mold surface, and combined with the surface quality of the parts performance, inspection, cleaning-based, supplemented by 800 # sandpaper polishing maintenance, in principle, do not use the oil stone polishing, in order to reduce long-term maintenance and polishing of the plating layer loss.
(4) mold type surface maintenance is completed, the use of roughness meter multi-point detection of surface roughness, to ensure that the surface roughness meets the standard requirements, to extend the life of the plating layer.
(5) After the end of production to the mold stretching groove of foreign objects, impurities, waste knife iron filings, cutting edge iron filings cleaned up.
Mold plating technology to solve the problem of case introduction of a model of front door inner plate due to cracks in the concave mold resulting in 100% strain on the part, the surface quality of the part is unqualified. In order to protect the mold production, mold maintenance personnel on the mold surface polishing, but every time after the production of dozens of pieces will appear again strain, resulting in mold stopping rate exceeds the standard. It increases the mold maintenance cost, reduces the production efficiency, and causes great trouble to the production of stamping workshop. By filling the die cracks with overlay welding and then electroplating, the problem of part strain was eliminated, and the quality and productivity of the parts were improved.
Die plating is an effective surface treatment technology, can effectively improve the performance of the mold and extend its service life, can improve the surface quality of the product, enhance production efficiency, reduce maintenance time and cost. Electroplating also has certain disadvantages: such as mold plating process operation is complex, need to strictly control the operation steps and time, so as to avoid uneven plating layer or fall off; plating process may produce waste liquid and exhaust gas, containing hazardous substances, pollution of the environment; plating also need to consider the cost of the problem, including the plating process of time and cost, the cost of different plating quality and type of cost is also different, increasing the economic burden on the enterprise The organic substances and metal ions in the plating solution may pose health hazards to the operators, and corresponding health protection should also be done. In short, with the continuous progress of science and technology and market demand continues to change, mold plating technology is also in constant development and innovation. For example, environmentally friendly plating: the use of cyanide-free and low-chromium plating process can reduce the pollution of the environment. Composite plating: two or more metals or alloys are deposited on the surface of the mold at the same time, forming a layer of composite plating with a variety of properties. Intelligent plating: Intelligent plating system to achieve real-time monitoring and control of the plating process, improve the quality of plating and production efficiency. In the future, mold plating will pay more attention to the development of environmental protection, high performance and intelligence to meet the market demand.