Encyclopedia of cost accounting methods for machining parts

       In recent years, the business of the machining industry has been sluggish, and cost control has become one of the ways for enterprises to reduce costs and increase efficiency. The machining process is complicated, how can we calculate the effective cost of the workpiece? After reading through the following, you will have mastered the essence of cost calculation, so take a serious look.



When the material cost is constant, the main difference lies in the different labor costs, transportation costs, consumption costs and taxes of each company. So how do most of these machining factories calculate?



The following editors have compiled some of the information for reference (because the calculation method varies from place to place)



Detailed calculation method:



1) First of all, you can ask the other party to provide preliminary process arrangements for key or complex parts, detailing each process and the time-consuming of each process.



2) The processing cost can be calculated according to the hourly cost of the equipment required for each process. You can also ask the supplier for the specific equipment cost. For example: ordinary vertical plus is between ￥60~80 per hour (tax included); ordinary equipment such as milling machine and general car is generally ￥30.



3) In accordance with the proportion of packaging and transportation, management costs, tooling tools, profit is the price. Of course, the price will have a lot to do with the annual purchase volume and difficulty of the parts to a certain extent. It is also easy to understand that there will be a lot of price difference between a single piece and a batch.



Rough estimation method:



1) For large pieces, the volume is larger and the weight is heavier.



General difficulty: The ratio of processing cost to the raw material cost of the entire part is about 1:1, which is inversely proportional to the purchase volume.



Difficulty: The ratio of the processing cost to the raw material cost of the entire part is about 1.2~1.5:1, which is inversely proportional to the purchase volume;



2) For small and medium pieces



General difficulty: The ratio of processing cost to the raw material cost of the entire part is about 2~3:1, which is inversely proportional to the purchase volume.



More difficult: The ratio of processing cost to the raw material cost of the entire part is about 5~10:1, which is inversely proportional to the purchase volume.



Due to the great process flexibility of machining, that is, a part can have many process arrangements, so the cost is of course different, but sometimes the supplier will quote you a complex process to increase the price, while the actual production Other simple processes will be used when purchasing, so the purchaser's own reading of drawings and knowledge of parts processing will determine your grasp of the cost, so the procurement of mechanical parts requires a more comprehensive knowledge of machining.



Machining costs are generally based on working hours



If you want to process a workpiece, first is the material cost of the other party; then some travel expenses (usually none) to purchase the workpiece.



The most important thing is the processing time required for the workpiece you want to process. Generally, the lathe is 10-20 yuan/hour, and the fitter is a little less about 10-15/hour; the rest are not listed.



If there are no ready-made tools (such as knives, molds), you need to bear part or all of the cost of the purchase; the final addition is the processing cost you have to pay!



Material costs, machine depreciation, labor costs, management fees, taxes, etc. are basically required. Or material costs, processing costs and taxes, as well as business costs, transportation costs, and budgeting requires a thorough understanding of the market.



Process issues should include material costs, processing costs (the processing price is different), equipment depreciation costs, worker wages, management fees, taxes, etc. It is mainly to first determine the process, that is, the processing method, and then calculate the man-hours according to the process, and determine the basic processing cost of a single part by the man-hours, plus other costs. Craftsmanship is a very complex knowledge, and a part adopts different craftsmanship, and the price is different.



Basic cost of working hours



In fact, the price of labor hours for various types of work is not fixed. It will vary according to the difficulty of the workpiece, the size of the equipment, and the performance. Of course, the key depends on your quantity, but generally speaking, it has a basic price. Floating between base prices.



1. Basic price of the car: 20-40



The specifics depend on the actual situation. For small pieces, the simple working hours are less than 20 yuan; sometimes it is even only 10 yuan.



For example, for some large pulleys, the machining allowance is large, and the boss only earns the money of cast iron powder; sometimes if the workpiece is large, the general market can not be processed, it can be higher, two or three times, no one else can.



2. Basic price of grinding: 25-45



3. Basic price of milling: 25-45



4. Basic price of drill: 15-35



5. The basic price of planing: 15-35



6. Basic price of wire cutting: 3-4/900 square millimeters



7. Basic price of EDM: 10-40, generally 50/piece for a single piece (less than 1 hour)



8. NC basic price: 2-4 times more expensive than ordinary ones



9. Engraving: generally single piece, 50-500/piece



The above prices are for reference only. If you have any experience, I hope you can also share it with us.



Due to different regions, different times, different manufacturers, different demanders, different suppliers, different quantities, there are many differences, and the prices are also very different, and there is no certainty. However, it is generally charged according to the processing hours, and a reference is as follows (the figures are only for reference, the regional and time differences are very large, this data does not include electrical processing, such as wire cutting, generally based on the area to be processed)



About the charging standard of general machining parts



1. The method of recording the price by working hours:



Z25 drilling machine, CA6140 lathe, planer, slotting machine and sawing machine are charged at 15 yuan per hour. Vertical and horizontal milling, wire cutting, large lathe, and gantry milling are charged at 20 yuan per hour. The general maintenance of fitters is charged at 15 yuan per hour. The timing unit starts from taking over the processing and ends when the processing is completed and the acceptance is passed.



2. The method of charging according to the parts, quantity and accuracy requirements:



1. Drilling general materials



If the depth-diameter ratio is not more than 2.5 times, the diameter of the drill is less than 25MM, and the diameter of the drill is 0.05. If the diameter is 25-60, the diameter of the drill is 0.12 (the minimum hole is not less than 0.5 yuan).



For general materials with a depth-to-diameter ratio greater than 2.5, the base price * depth-to-diameter ratio * 0.4 will be charged. If the aperture accuracy is less than 0.1MM or the center distance is less than 0.1MM, the base price * 5 will be charged.



The charging standard for tapping is charged according to the tap diameter * 0.2 (take cast iron as the standard, and steel parts are additionally * 1.2), and in batch processing, the standard base price * 0.2-0.8 (according to the batch size and processing difficulty).



2. General precision optical axis processing for lathe processing



If the aspect ratio is not larger than 10, the charge is based on the blank size of the workpiece * 0.2 (the bottom is 5 yuan).



If the aspect ratio is greater than 10, it will be charged according to the general optical axis base price*aspect ratio number*0.15, and the precision requirement is within 0.05MM or the taper is required to be charged at the general optical axis base price*2.



General stepped shafts (fan shafts, pump shafts, reducer shafts, grinding wheel shafts, motor shafts, spindles, etc.) are charged at the base price for general-precision optical shaft processing*2. If the stepped shaft has tapers, internal and external ribbing, it will be processed according to general-precision optical shafts The base price*3 is charged.



The general-purpose lead screw is charged at the base price*4 for general-precision optical axis processing.



Generally, flange parts are charged according to the material diameter * 0.07, and those with a diameter greater than 430MM are charged according to the material diameter * 0.12.



General round nut parts are charged according to diameter * 0.25 (including materials).



Generally trapezoidal, triangular nut parts according to diameter * 0.3 (excluding materials).



General shaft sleeve parts (diameter less than 100 diameter to length ratio less than 2) are charged according to the material outer diameter * 0.2, and the diameter to length ratio exceeds 2 according to the diameter to length ratio * base price * 0.6.



Generally, the wear amount of the parts of the bearing platform is less than 2MM, the diameter is less than 40MM and the width is less than 25MM, each 5 yuan, needs to be placed on the center frame, or the base price*2 is charged for the length greater than 1.7 meters. If the diameter is larger than 40MM, it will be charged as diameter*0.2.



3. General keyway processing for milling machine processing



(Aspect ratio is less than 10) key slot width * 0.5 charge (minimum 5 yuan). If the aspect ratio exceeds 10, it will be charged according to the aspect ratio * base price * 0.1.



If there are strict location requirements, the base price*2 will be charged.



The processing of materials with hardness greater than HRC40 will be charged at the base price*2.



General spline processing (length-diameter ratio less than 5) is charged according to the outer diameter of the spline shaft * 0.8 (minimum 15 yuan).



Generally, the processing of gears is charged according to the module * number of teeth * 0.5 yuan. The worm gear is charged according to the base*1.2. Helical gears, bevel gears, and displacement gears are charged at the base price*2.



General plane processing is charged at 1.5 yuan per square decimeter (minimum 5 yuan).



Generally, the boring processing is charged according to the hole diameter * 0.25.



4. Band saw processing



General round steel, thick-walled pipe, square steel cut off, calculated at 5 yuan per square decimeter (minimum 5 yuan), general steel plate cutting, slitting, opening angle at 10 yuan per square decimeter (minimum 10 yuan).



5. Wire cutting



General parts are charged according to the cutting area (square millimeter) * 0.008 yuan. The parts that need to be threaded will be charged an additional 5 yuan per threading hole.



6. Electric welding, gas cutting and plasma cutting



Ordinary electrodes with a diameter of 3.2 are 1 yuan each, and TH506 welding castings are 3 yuan each. For gas cutting processing, the plasma cutting stainless steel is calculated according to the iron plate thickness MM * cutting length M, and the gas cutting base price * 3 is charged, and the cutting carbon steel is charged at the gas cutting base price * 2.



7. About special expedited items and overtime items



The special expedited parts charged at the standard base price*2 are defined as: the first time to arrange to repair or manufacture urgent parts for a specific customer. Overtime parts are parts that must be continuously manufactured beyond normal working hours.



Optical tool curve grinding processing fee 60 yuan / hour,



200 lathes, 20 yuan/hour,



30 yuan/hour for a lathe above 300,



Milling machine 20 yuan/hour, drilling 15 yuan/hour,



Boring machine 35 yuan/hour,



Grinder 30 yuan/hour,



Slotting bed 15 yuan/hour,



Bull head planer 20~25 yuan / hour,



Longmen planing and milling 30 yuan / hour,



Rolling machine (rolling steel plate thickness below 20) 60 yuan / hour,



C620.C6140 is basically 20 yuan an hour,



30 lathes are 30 yuan an hour,



Vertical lathe (60 yuan per hour for a lathe,



Rocker drill is 20 yuan an hour,



T68 boring machine 30 yuan per hour,



Small vertical milling and horizontal milling for cattle planing is 20 yuan an hour,



Gantry milling and gantry planing is 60 yuan an hour,



400 square meters and 20 yuan per hour for a bed with a diameter of less than one meter,



It is 60 yuan an hour three meters away,



The machining center is 80 yuan per hour (the same as the number of milling and turning),



Electric welding and gas cutting is basically calculated by pieces, and it is not convenient to calculate at 30 yuan per hour.



The fitter assembles 20 yuan an hour.



In addition, the labor payment is also related to the number of outsourced processing. The working hours of finishing processing are as follows:



Fine grinding tolerance 0.005 40 yuan / hour,



Spark tolerance 0.01 80 yuan / hour,



Slow walking wire tolerance 0.005 100 yuan / hour,



The tolerance of the light warp grinding is 0.003 180 yuan/hour.