Custom Mold Base Machining Workflow | P20/45 Steel Supply, Duplex Milling, Vertical Machining Integration

In P20/45# steel processing, first need to select high hardness steel to ensure mold's durability.

Adopt double-station milling technology, improve processing precision and efficiency, especially applicable to complex cavity molds.

Vertical processing integration can realize simultaneous processing of multiple processing surfaces, improve production efficiency.

For P20/45# steel, recommend use cutting speed of 150-200 meters/minute, feed speed of 0.1-0.2 mm/rev.

P20/45# Steel Supply

Specifications & Performance

45# steel's carbon content needs to stabilize at 0.42% to 0.50% between. If manganese element ratio lower than 0.50%, steel in large specification plate state's hardenability will obviously decrease, leading to thick plate center position hardness unable to reach 170HB. This hardness drop will lead to subsequent deep hole processing when drill bit force uneven, generate 0.15mm above radial deflection.

Low-end 45# steel's sulfur, phosphorus impurity content usually will exceed 0.045%. In vertical machining center at 200m/min linear speed cutting, these microscopic impurities will induce alloy blade generate 0.1mm micro chipping. Impurity content every increase 0.01%, tool's use life will correspondingly shorten about 20%.

Incoming plate's flatness error needs to control within per meter 2mm. Thickness in 30mm to 80mm 45# steel plate, saw-cut side's verticality deviation must be smaller than 0.5mm.

P20 mold steel's delivery hardness usually set at 285HB to 330HB. Its internal containing 1.4% to 2.0% chromium element improved oxidation resistance. If chromium content insufficient 1.2%, mold base in humidity 60% workshop storage exceeding 48 hours, surface will generate naked eye visible rust spots, affect finishing benchmark.

· Molybdenum element proportion in P20 should be between 0.30% to 0.55%.

· Molybdenum content reaching standard can let steel under 300 degrees high temperature strength attenuation drop to within 10%.

· This metal ratio can guarantee 1500rpm speed under drill bit's heat conduction efficiency improve 15%.

· Nickel element's adding amount usually at 0.2% around, used to enhance material's low temperature impact toughness.

· Silicon content must be suppressed below 0.40%, avoid material under injection pressure generate fatigue cracks.

Ultrasonic flaw detector uses 2.5MHz frequency probe to perform all-round scanning on steel plate. Refer to SEP 1921 standard, plate internal if exists diameter exceeding 2mm gas pores, or each square centimeter's inclusions exceed 3, this batch steel will be marked as waste product.

Steel internal's grain size level needs to reach level 7 in GB/T 6394 standard. If grain size too coarse, polished mold surface will appear orange peel resembling texture. High quality P20 can support 600 grit or even 1000 grit sandpaper fine polishing, Ra value can stabilize below 0.1 micron.

Raw material's length direction must reserve 4mm to 6mm processing allowance. Thickness direction leave 3mm. These redundant spaces are to ensure double-side milling process can thoroughly cut off 0.8mm thick surface decarburization layer.

· After vacuum degassing treatment P20 oxygen content must lower than 15ppm.

· Sulfur content controlled below 0.005% can improve EDM surface flatness.

· Steel's thermal conductivity is 34 W/m·K, this determines cooling waterway's arrangement efficiency.

· Thermal expansion coefficient stays between 11.5 to 12.5, affects mold's dimensional stability at 200 degrees.

· Yield strength reaches 850MPa above, prevents mold base at middle plate support position occurring plastic deformation.

Thickness exceeding 100mm large 45# steel plate after sawing needs to perform stress relief annealing. Heating temperature controlled at 580 degrees Celsius, insulation time is 180 minutes. Cooling speed needs to strictly execute 30 degrees per hour standard. Cooling too fast will lead to residual stress exceeding 20%, induce deformation after finishing.

P20's hardness deviation on same plate cannot exceed plus or minus 1HRC. Use Leeb hardness tester at plate center and four corners respectively take points, if difference value greater than 3HB, indicates steel during heat treatment cooling suffered uneven heating.

In 45# steel's finishing stage, cutting specific energy approximately is 2.5 GPa. If supplied material hardness fluctuation exceeds 20HB, machine spindle's current load will generate 8% jump. This fluctuation will reflect on processing surface, generate perceivable vibration marks, Ra value will from 1.6 micron worsen to 3.2 micron.

· Steel plate surface's mechanical scratch depth strictly prohibited exceeding 0.5mm.

· In wire cutting processing, non-metallic inclusion length should be smaller than 0.1mm.

· Qualified P20 material can reduce wire cutting wire-breaking rate 25% above.

· Sawing tolerance needs to narrow within plus 2mm, reduce double-side milling's chip amount.

· Steel material certificate's furnace number must with physical spray code 100% correspond.

Steel's elastic modulus is 210GPa, this is physical basis for calculating mold base force deformation. Select steel produced by refining furnace, its internal structure density higher. When bearing 50 tons above mold-clamping pressure, high purity P20 can reduce 0.01mm micro-deformation, extend mold overall use life.

Quality Verification Standards

Direct-reading spectrometer performs excitation detection on incoming steel, probe releases high-voltage electric spark instant, through refractive spectrum locks carbon, chromium, manganese's percentage concentration. P20's sulfur content must control below 0.005%. Sulfide once exceeding standard, in double-side milling will form long-strip non-metallic inclusions, leading to processing surface generate naked eye visible wire-like peeling, roughness Ra value will directly from 0.8 micron worsen to 1.6 micron.

45# steel's carbon content measured value if lower than 0.42%, steel's yield strength will from 355MPa drop to 310MPa around. This material strength insufficiency will induce mold base when under pressure generate micro plastic deformation, long-term use will lead to mold base middle plate's parallelism over-tolerance.

P20's hardness should stay between 285HB to 330HB, same template's diagonal hardness difference strictly prohibited exceeding 10HB. If hardness difference reaches 15HB above, vertical machining center when performing thread milling, spindle load jump will exceed 10%, this will lead to different hole positions' thread tolerance zone generate 0.02mm offset.

Ultrasonic flaw detector needs to cooperate with 2.5MHz to 5MHz frequency longitudinal wave probe. After evenly applying coupling agent on steel plate surface, scanning speed controlled within 150mm per second. Refer to SEP 1921 standard, internal single defect's waveform height if exceeds bottom wave's 50%, or dense defects lead to bottom wave drop exceeding 12 decibels, this piece of steel must scrap. For thickness exceeding 150mm P20, internal defect diameter cannot exceed 2mm, otherwise when fine cutting cavity will expose sand holes.

P20 internal's non-metallic inclusions rating needs to reach A, B, C, D all categories smaller than 1.5 level's level. Inclusions if reach 2.0 level above, EDM discharge will generate local arc, leading to mold cavity surface generate depth about 0.05mm burn pits, repairing such defects often needs to increase 20% above grinding man-hours.

· During flaw detection, bottom wave height must maintain at 80% above of display screen full scale.

· 45# steel's grain size needs to reach 5 to 7 level, ensure mechanical cutting after tensile strength reaches 600MPa.

· P20's Cr content fluctuation needs to control in 1.4% to 2.0% interval, guarantee anti-corrosion ability.

· Each batch steel material certificate (MTR) needs to include furnace number, chemical composition and mechanical properties.

· Steel plate surface decarburization layer measured depth should smaller than 0.8mm, prevent initial cut after hardness drop.

· Dimension tolerance in length direction needs to maintain within plus 5mm, reduce redundant chips.

Aimed at thickness exceeding 100mm large templates, stress release process after detection data is judgment basis. Under 580 degrees Celsius environment constant temperature 180 minutes after, plate's residual stress should drop to 50MPa below. If residual stress exceeds 80MPa, subsequent in vertical machining center cutting off 50% above material allowance, plate will generate exceeding 0.1mm bow-shape warping, leading to mold base unable to close.

Under metallographic microscope, 45# steel's structure should be uniform ferrite plus pearlite, strictly prohibit appearing coarse Widmanstätten structure. Widmanstätten structure's existence will make material's impact energy from 30J decrease to 10J below, leading to mold base when suffering mold-clamping instantaneous impact force occurring fracture. P20's microstructure then needs to present uniform tempered sorbite, this structure can support it at 32HRC hardness under still possessing good polishing performance.

· Random inspection proportion set as each batch incoming volume's 15%, focus covering large size plates.

· When measuring end face verticality, use 0-level precision square ruler, deviation needs to control within 0.5mm/m.

· Check steel side spray code, content must include manufacturer, steel grade, furnace number and size.

· P20's oxygen content detection value needs lower than 15ppm, prevent oxide-induced mirror flaws.

· Use Leeb hardness tester perform inspection, each square meter take points no less than 9, calculate average value.

Within 1000mm length flatness deviation strictly prohibited exceeding 2mm. If flatness error reaches 3mm above, double-side milling machine clamping will generate huge pre-stress. Once cutting finished releasing pressure plate, steel plate will because of stress rebound generate 0.05mm above distortion, destroy mold base each template between's fit tolerance.

Aimed at high precision mold base used P20, molybdenum content must measured at 0.30% to 0.55% between. Molybdenum element is guarantee section hardness uniformity's key, it can let diameter 500mm round steel from surface to core's hardness difference control within 3HRC. If molybdenum content lower than 0.2%, core hardness will drop to 25HRC below, leading to mold in use 20,000 mold cycles after appearing center position collapse deformation.

P20 under room temperature thermal conductivity should stabilize at 34 W/m·K. If because impurities too many lead to thermal conductivity decrease to 30 W/m·K below, mold in production process's cooling cycle efficiency will decrease 12%, directly extended molding cycle, increased customer's production cost.

Processing Pre-treatment

Use GZ4280 horizontal band saw machine to perform physical cutting on P20 blank, blanking tolerance locked in plus 3mm to plus 5mm. If allowance lower than 2mm, double-side milling machine when aligning first side will lead to cutting depth insufficient, unable to thoroughly remove surface thickness about 0.5mm oxidation scale.

Saw band speed set at 45m/min, cooperate concentration 8% synthetic emulsion. Temperature too high will lead to 45# steel saw-cut surface generate thickness 0.2mm heat-affected hardening layer. This will increase subsequent rough milling processing's blade loss, make single blade's effective cutting life shorten about 30%.

Place plate in trolley-type resistance furnace, at 80 degrees Celsius per hour speed heat up to 580 degrees Celsius. Constant temperature duration according each 25mm thickness insulation 1 hour calculate, ensure plate internal and external temperature difference control within 5 degrees Celsius.

· Blanking end face's verticality deviation controlled within 0.8mm/200mm.

· P20 material cut off after residual stress through vibration aging equipment process 35 minutes.

· 45# steel surface rust layer through shot blasting machine process, abrasive diameter select 0.8mm steel shot.

· Sawing generated flashing burrs use 120 grit angle grinding disc clear.

· Large template bottom surface pre-grind out three support points, flatness deviation not exceed 0.03mm.

· Pre-processing stage benchmark angle marking use 0.5mm depth steel stamp.

Steel before entering double-side milling station, through ultrasonic cleaning remove surface attached oil dirt. Residual oil grime under cutting heat action will generate carbon deposition, make processing roughness Ra value from 1.6 micron drift to 3.2 micron, increase subsequent process 40% grinding amount.

Use precision flat-nose pliers clamp 45# steel side, initial milling depth controlled at 1.5mm. Use dial indicator detect side generatrix, ensure 500mm length within straightness error smaller than 0.015mm.

P20 steel in pre-processing link needs to check surface hardness uniformity. In 300mm by 300mm area randomly extract 5 points, hardness difference if exceeds 2HRC, indicates material internal exists segregation. This when feed speed reaches 2500mm/min, will induce tool holder generate 3 micron simple harmonic vibration.

· Pre-heat treatment after cooling rate strictly prohibited exceeding 30 degrees Celsius per hour.

· Use magnetic chuck clamping, shim thickness error calibrate to 0.005mm.

· 45# steel template pre-cut after total deformation measurement value should lower than 0.05mm.

· P20 material surface spray anti-rust diluted oil, oil film thickness control at 15 micron.

· Lifting screw hole pre-drilling depth tolerance maintain in plus 2mm to plus 5mm.

· Benchmark surface R angle clearing use diameter 10mm ball-nose milling cutter.

Aimed at thickness 150mm above heavy mold base, pre-processing needs to increase secondary tempering. Under 550 degrees Celsius stress release efficiency can reach 92%. Untreated plate in deep hole processing to 200mm depth, drill bit deflection probability will improve 60% above.

45# steel's elastic modulus is 210GPa. In pre-stress clamping process, pressure plate locking torque through torque wrench controlled at 120Nm. Pressure too large will lead to plate generate 0.01mm micro deflection, after releasing fixture, originally milled flat surface will recover to concave surface.

P20 material's thermal conductivity is 34 W/m·K. In pre-processing stage, if adopting dry cutting, cutting zone instantaneous temperature will soar to 700 degrees Celsius. This will change steel surface layer's metallographic structure, form thickness about 0.05mm martensite layer, leading to subsequent finishing appear tool breaking phenomenon.

· Rough milling first cut depth control at 2.0mm, speed set at 800rpm.

· Use thickness gauge perform measurement on four corners, thickness difference control within 0.15mm.

· Pre-processing stage cutting fluid refractive concentration maintain between 6.5% to 7.5%.

· 45# steel template lifting hole verticality deviation strictly prohibited exceeding 0.1mm.

· P20 material surface clear all depth exceeding 0.3mm saw marks/scars.

· Clamping position clearance hole diameter needs to be 2mm larger than bolt, prevent force interference.

Before precision milling benchmark surface grinding needs to reach 0.02mm flatness. For 45# steel, select WA60 medium-soft grade grinding wheel, spindle speed 1450rpm. Infeed amount controlled at single 0.01mm, avoid grinding heat leading to surface generate micro-cracks.

Use spectrometer to perform secondary re-check on P20 plate cut section. Silicon content if measured exceeds 0.40%, in pre-processing drilling link needs to lower feed rate 20%. High silicon content will make drill tip wear speed increase 1.5 times, increase tool replacement frequency and downtime.

· Pre-processing record needs to include each plate's initial weight, precision reaches 0.5kg.

· Steel plate all around edges perform 45 degree chamfer process, chamfer width 2.0mm.

· 45# steel after normalizing structure's sorbite content should reach 90% above.

· P20 after pre-processing standing time no less than 12 hours, let structure stress naturally release.

· Drilling center positioning hole diameter deviation control within plus 0.01mm.

Because 45# steel at 20 degrees Celsius linear expansion coefficient is 11.5 micron per meter Celsius. Pre-treatment workshop's temperature difference needs to control in plus or minus 5 degrees Celsius. Environment temperature fluctuation exceeding 10 degrees Celsius, will make 500mm length plate generate 0.05mm size drift, destroy pre-processing alignment precision.

Duplex Milling

Parallelism & Verticality

P20 modules or 45# steel blanks delivered from steel mills, surfaces often carry 2mm around black oxidation scale, internal accumulates huge amount of rolling stress. If directly put this 400mm wide plate on single-head milling machine, cutting after one side then flipping, steel will like banana occur 0.3mm above warping.

Double-side milling machine equipped 315mm diameter cutter disk at both sides simultaneously cut in, speed constant at 140 revs around. Two sets of cutting forces at steel plate center position occur cancellation, originally would lead to deformation 2000 kg lateral thrust in internal mutually cancel. This operation let template after removing 3mm allowance, still maintain extremely high physical dimension stability.

Processing P20 this pre-hardened to HRC 30 around material, feed amount set at each tooth 0.15mm. If for catching speed increase to 0.25mm, tool tip temperature will instantaneous exceed 650 degrees, leading to cutting edge chipping. Through precise control feed, 500mm length within parallelism can deathly lock in 0.01mm tolerance range.

· Tool spindle runout: measured must in 0.003mm range.

· Side roughness: Ra 1.6 to Ra 2.4 between, hand feeling no obvious tool marks.

· Tool blade coating: select TiAlN material, thermal shock resistance supports continuous cutting 8 hours.

· Dimension repeatability: one batch 30 pieces templates, thickness error controlled in 0.02mm fluctuation.

45# steel's cutting linear speed can put to per minute 200 meters, far higher than P20. Although hardness low, but this steel's plasticity large, easy to stick tool. Double-side milling through per hour 45 ml micro-lubrication spray, reduced tool tip and steel surface friction coefficient, prevented surface generate tear-like burrs.

Verticality relies on machine tool's own 90 degree geometric precision to guarantee. When first set of parallel surfaces milled finished, worktable rotate 90 degrees processing other two sides, double-head milling machine's turntable positioning precision determines finished product's squareness. At 300mm height, adjacent two sides vertical error will be compressed to 0.015mm within.

· Auto centering time: probe sensing positioning only needs 80 seconds.

· Hydraulic clamping force: 2.8 tons constant pressure, prevent cutting vibration.

· Tool change frequency: processing P20, each 15 plates flip once blade edge.

· Worktable load: support highest 2500 kg heavy mold blank.

If this step's verticality deviated 0.05mm, subsequent entering vertical machining center drilling, drill bit will carry tilted angle downward. Processing a 250mm deep guide pillar hole, hole bottom position will occur 0.12mm offset.

When VMC machining center detects side, because surface enough flat, picked zero point coordinates overlap degree reaches 0.005mm. This precision supports subsequent all cavity and waterway hole positioning, let whole set mold's mold-clamping gap stabilize at 0.02mm level.

Temperature on precision's interference very direct, steel every increase 1 degree, every meter length will extend 12 micron. Double-side milling through symmetric removing material, let cutting heat at both sides evenly distribute, avoided single side heated induced plate arching. At 24 degrees constant temperature environment, just off machine template flatness measured is 0.005mm.

Stress Release

P20 pre-hardened steel out of factory from steel mills internal lurks huge residual stress, this stress sources from material in HRC 28-32 hardness treatment when violent cooling process. In one 500mm square thick plate, internal stress distribution extremely complex, if adopting single-side milling machine forcedly peeling surface 2mm skin material, steel plate internal balance will be instantaneously broken.

Single-side cutting finished, plate often will toward un-processed that side occur 0.3mm to 0.6mm concave warping.

When 250mm diameter disk milling cutter at per minute 140 meters linear speed cut in, generated heat will make cutting zone local heat up to 200 degrees Celsius above. Double-side simultaneous processing let these heat symmetrically from outside to inside conduct, avoided single side heated expansion induced physical bending. This temperature control logic makes template after cooling to 20 degrees Celsius room temperature, length direction expansion/contraction error maintains within 0.01mm.

· P20 steel stress release amount: single side processing deformation 0.45mm, double-side simultaneous processing deformation smaller than 0.05mm.

· 45# steel heat affected depth: feed amount 0.25mm, surface below 0.15mm area exists thermal stress accumulation.

· Cutter disk sync error: both sides tool tip cut in time difference control within 0.02 second, prevent plate generate vibration.

· Hydraulic support pressure: constant at 2.5 tons to 3.0 tons between, cancel cutting vibration induced secondary stress.

· Residual stress elimination rate: after double-side fine milling template, natural aging 24 hours after size change amount lower than 0.008mm.

Double-side milling machine adopts four-point positioning hydraulic clamping mechanism, this mechanism distributes 3000 kg gripping force evenly on template non-processing surface. If clamping force points improper, steel plate at instant of releasing fixture will generate 0.02mm elastic recovery, leading to previously milled flat surface no longer flat.

In processing 45# medium carbon steel, this material's plasticity stronger than P20, cutting easy to generate ribbon-like chips. Double-side milling cooperate high pressure air-cooling system, per minute 500 liters cold air when taking chips away, also took away 85% above cutting heat.

· Cooling air pressure: Maintain at 0.6MPa, ensure tool tip temperature not higher than 180 degrees Celsius.

· Depth control: Rough processing single side 3mm, fine processing single side 0.5mm, stage-by-stage release stress.

· Spindle speed fluctuation: Load fluctuation control within 5%, avoid speed suddenly fast/slow caused surface internal stress.

· Fixture contact area: Each pressure foot contact area no smaller than 400 square millimeters, reduce local compressive stress.

If ignored double-side milling in stress release details, subsequent on vertical machining center (VMC) milling cavity, along with large amount material being dug away, template will occur secondary deformation. Originally in double-side milling link laid benchmark surface will because internal residual stress burst and fail, leading to cavity center position occur 0.08mm offset.

Through this physical balance processing way, P20 mold base's geometric centerline and material's force center line realized high degree overlap. In subsequent as long as 500,000 times mold-clamping cycles, template will not because fatigue stress generate creep. This from bottom layer solving metal temper process, ensured mold in high temperature high pressure injection environment still can maintain 0.015mm mold-clamping precision.

· Aging period: After fine milling suggest standing 12 hours, measured size spring-back rate usually at 0.003mm.

· Blade wear monitoring: When tool tip wear exceeds 0.2mm, cutting force will increase 30%, must immediately replace to prevent forced cutting generate new stress.

· Turntable reset precision: Rotate 90 degrees processing other two sides, mechanical positioning precision must deathly guard at 0.005mm.

· Material removal rate: Per minute remove 150 cubic centimeter volume steel, efficiency compared traditional way higher 2.5 times.

Processing Efficiency Improvement

In 500mm by 500mm P20 mold base plate processing, traditional single-head milling machine's clamping and aligning link occupied total man-hours 40% above. Operator needs use dial indicator on steel plate four sides perform back and forth toggle, ensure parallelism falls into 0.05mm range. Double-side milling machine equipped infrared probe at 200mm/s speed contact material edge, in 85 seconds automatically complete coordinate system offset.

Hydraulic auto-centering mechanism provided 3 tons clamping force instantly acting on plate center, saved manual knocking shim leveling steps. This automation clamping cooperate double spindle simultaneous cutting, let originally need 20 minutes preparation work compress to 2 minutes. Workshop measured data shows, single unit double-side milling machine's daily processing capacity is traditional equipment's 3.5 times, significantly shortened mold base in rough processing zone's stay time.

· Spindle motor power: double-way independent 22kW variable frequency spindle.

· Cutter disk configuration: diameter 315mm 14-tooth heavy load carbide milling cutter.

· Automation tool setting: repeat positioning precision reaches 0.002mm.

· Feed response speed: fast moving speed reaches 12m/min.

· Chip handling efficiency: spiral chip conveyor each hour outputs 40kg waste metal.

A certain mold factory in processing a set containing 12 pieces P20 plate parts non-standard mold base, adopting single-side milling needs total 16 hours cutting man-hours. Change to double spindle simultaneous work after, total time dropped to 5.5 hours, including twice 90 degree auto turntable's rotation time.

Spindle when cutting into 45# steel, cutting linear speed set at 210m/min, feed speed high as 600mm/min. Two sets of cutter disks under 3mm depth simultaneously peel oxidation scale, generated cutting resultant force in workpiece internal cancel, prevented plate because single side force generated 0.02mm jump.

Aimed at P20 pre-hardened steel, because material hardness at HRC 30 around, double-side milling through decreasing 15% rotation speed to exchange more stable cutting pressure. Double head sync not only is time saving, more avoided single head processing middle because of multiple head turning, re-aligning table caused 0.03mm cumulative error.

· Blade use life: Single set edge can continuous process 45,000 square centimeter area.

· Power consumption: Compared two units single-head milling machine, double-head sync cutting energy saving about 18%.

· Labor operation: One technician can simultaneously look after 3 units double-side milling equipment.

· Clamping cycle: From lifting to start processing, cycle time controlled within 180 seconds.

· Standby loss: Spindle start-stop response time shortened to 1.2 seconds.

In high intensity 24 hours continuous operation, double-side milling machine's failure downtime rate far lower than multiple units single machine combination. Because reduced 50% head-flipping mechanical actions, reduced machine tool guide rail and lead screw's frequent back and forth loss.

Heavy 2-ton level template's lifting is workshop efficiency's bottleneck, each head flip needs crane cooperation. Double-side milling through one-time clamping completes two parallel surfaces fine cutting, crane use frequency reduced by half. This handling rhythm's slowing, indirectly improved workshop overall logistics flow efficiency, avoided crane in multiple units machine tools between queuing waiting's idle work phenomenon.

Cutting zone equipped atomization cooling system with 0.5MPa pressure spray, quickly takes away two sets of cutter disks generated heat. This symmetric heat dissipation mechanism guaranteed P20 steel surface will not appear local hard spots, thus letting subsequent VMC drilling's drill bit life improved 20%.

Vertical Machining Integration

Structural Characteristics

BT50 spindle compared common BT40 spindle increased 2.5 times shank contact area. Processing P20 pre-hardened steel, this heavy interface can absorb per minute 3000 revs generated high frequency vibration. Spindle front end configured four-row angular contact ball bearings, radial runout precision maintains at 0.002mm.

HT300 gray cast iron machine body through secondary manual aging treatment, eliminate internal stress. 800kg weight 45# steel template placed on worktable center, bed middle sinking displacement amount controlled within 0.008mm. Three axes all adopt width 45mm ball linear guide rails, bearing capacity reaches each slider 5000kg.

· Machine spindle rated power: 15kW

· Worktable travel span: 1200mm x 600mm

· Tool change arm speed: 1.8 seconds (tool to tool)

· Three axes rapid positioning speed: 36m/min

· Minimum command unit: 0.001mm

· Spindle constant temp system temp difference control: +/- 1 deg C

· Tool holder dynamic balance grade: G2.5 25000RPM

· Servo motor encoder resolution: 24-bit

Three axes ball lead screws select C3 grade precision grinding parts, double nut pre-tightening force set at 3000N. Lead screw both ends support bearings use precision lock nuts fix, eliminate axial movement caused backslash. In 300mm travel, lead screw's pitch error measured value lower than 0.005mm.

Aimed at HRC 30 around P20 steel, vertical machining adopts 35 degree helix angle tungsten steel end mill. Rough milling stage cutting speed set at 120m/min, each tooth feed amount maintain at 0.12mm.

2.0MPa pressure spindle center water outlet system directly flushes deep hole bottom. Drilling 45# steel guide pillar hole, chips are high pressure fluid quickly brought out chip groove, avoid long chips scratch hole wall. Diameter 20mm deep hole one time downward drilling depth can reach 150mm, without multiple times retreat tool discharging chips.

· Surface processing roughness value: Ra 0.4 - Ra 0.8 micron

· Parting surface parallelism error: 0.015mm / 300mm

· Guide pillar hole position tolerance: +/- 0.01mm

· Thread hole effective depth deviation: +/- 0.5mm

· Chamfer edge consistency: 0.5mm x 45 degrees

· Fine boring hole roundness: 0.005mm

· Side wall verticality deviation: 0.01mm / 100mm

· Template four corners diagonal error: 0.02mm

Infrared probe cooperate Renishaw OMP60 system perform online detection. Program every running 30 minutes auto return origin scan benchmark surface. If detected P20 steel because thermal expansion contraction generate 0.01mm size drift, system will auto in compensation value write in difference value, guarantee subsequent hole position precision.

45# steel plate in drilling water transport hole, speed set at 2200RPM. U-drill's high hardness blade can bear each revolution 0.15mm extrusion feed. Measured 10 mold base samples, 300mm deep hole's exit offset all maintain in 0.3mm to 0.5mm interval, not interfere internal ejector components.

Machine tool side equipped large flow auto chip conveyor, each hour can transport 150kg iron chips. Chiller unit on emulsion perform cycle filtering, impurity granularity control within 20 micron.

· Three axes servo motor torque: 22Nm

· Lubrication oil pump supply cycle: 20 min/time

· Machine total weight: 7.5 tons

· Tool magazine capacity: 24 BT50 tools

· Coordinate system repeat alignment precision: 0.003mm

· Lead screw bearing seat positioning pin precision: h6 standard

· Bed static stiffness coefficient: 180N/micron

P20 fine milling surface generated cut mark spacing set at 0.05mm. Through high speed scanning (Look-ahead) function, system ahead preview 1000 program segments. In processing mold cavity R angle, feed speed auto from 1200mm/min decrease to 400mm/min, eliminate corner position over-cut risk.

Guide bush hole's processing adopts double-edge rough boring and single-edge fine boring combination. Fine boring tool head each adjust one small grid represents 0.002mm diameter increment. Processing finished hole internal wall presents mirror reflection effect, measured hole diameter conforms H7 level standard, deviation value falls between +0.021mm and 0mm.

Material Adaptation

P20 pre-hardened steel out of factory hardness maintains in HRC 28 to 32 interval. Vertical machining center processing this material, cutting speed fixed at 120 to 150m/min. 12mm diameter four-edge coated milling cutter, speed set at 3200RPM, each tooth feed amount controlled at 0.08mm.

35 degree helix angle carbide tool reduced cutting resistance. Processing P20, radial cutting depth (Ae) maintain at 1.2mm, axial cutting depth (Ap) set at 18mm. High pressure emulsion through 2.0MPa pressure flush cutting zone, maintain tool tip temperature lower than 220 degrees Celsius.

45# medium carbon steel hardness distribute between HB 160 to 200. Rough processing stage, cutting speed improve to 180m/min. Adopt wave-edge rough milling cutter, each minute metal removal rate reach 150 cubic centimeter. Because this steel toughness large, chip groove space needs occupy tool cross-section 40% above.

· P20 finishing use AlTiN coated tools, anti-oxidation temp reaches 900 deg C.

· Side wall fine milling allowance leave 0.15mm, divide twice pass eliminate tool deflection error.

· Measured P20 processing surface roughness stabilizes at Ra 0.6 micron.

· 45# steel drilling speed fixed at 1200RPM, feed speed 280mm/min.

· Use U-drill processing 45# steel waterway hole, each rev feed amount 0.12mm.

· Tapping P20 deep hole needs cooperate with high extreme pressure additive special cutting oil.

45# steel under high temperature cutting easy to generate built-up edge. Tool rake face wear amount reaches 0.3mm when, workpiece surface will appear obvious tear marks. Replace new blade after, through increase 30% coolant flow, can lower built-up edge generation probability.

P20 steel alloy element content higher, cutting force than 45# steel higher about 25%. Spindle servo motor load rate shows, milling P20 when current waveform amplitude is 15A, while processing 45# steel when amplitude maintain at 11A. This load difference determines fixture locking force needs reach 5000N above.

· Fine boring P20 guide pillar hole, cutting depth Ap limited at 0.05mm.

· Boring tool linear speed controlled at 80m/min, prevent generate thermal deformation displacement.

· Measured hole diameter roundness error maintain within 0.005mm.

· 45# steel template chamfer adopt speed 6000RPM single-edge chamfering tool.

· Chamfer width uniformity deviation smaller than 0.03mm.

· P20 deep cavity bottom corner clearing use R0.5 round-nose tool, reduce stress concentration.

P20 material mold base side flatness each 300mm error is 0.01mm. Adopt interchangeability detection method, two finished templates face to face, mold-clamping gap use 0.02mm feeler gauge unable to plug in.

45# steel processed thread holes, through standard plug gauge detection. Go-gauge smooth screw in, stop-gauge after enter 2 revs naturally lock death. Thread pitch diameter tolerance zone falls in 6H level, single hole processing time shortened to 12 seconds. Large batch processing when, each 200 holes check once tool tip wear state.

P20 steel thermal expansion coefficient is 12.8 multiplied by 10 negative 6th power. Environment temperature change 5 deg C, 500mm long template will generate 0.03mm size change. Processing workshop constant temp system room temp fluctuation control in plus or minus 2 deg C, ensure precision hole positions' coordinate consistency.

Aimed at 45# steel workpieces, surface oxidation layer thickness before processing needs through rough milling process remove 3mm. Bottom shim height difference compensation value set at 0.002mm. Worktable move 1000mm travel, machine laser interferometer reading shows linear compensation amount is 0.004mm.

· Spindle torque output: Processing P20 when reaches 45Nm.

· Cutting force monitor: X axis load rate maintain at 35%.

· Tool change point height: Z axis reference point set as 200.000.

· Chip morphology: P20 presents short C shape, 45# presents long coil shape.

· Probe calibration cycle: Every 24 work hours automatically execute.

· Fine milling join mark height: Smaller than 0.003mm.

P20 material in milling process shows good dimensional stability. Fine processing program run 2 hours, spindle box thermal compensation value is 0.015mm. Through FANUC system's AI thermal compensation algorithm, actual processed cavity depth error controlled within 0.005mm.

45# steel template lifting hole processing adopts 14mm drill bit, speed 800RPM. Each hole cutting fluid consumption about 150 ml, through cycle filtering system recovery reuse.

Integration Three Elements

UG software exported STEP format file load into vertical machining center control system, 0.001mm path resolution avoided hand-written code generated coordinate errors. Machine tool each second process 2000 program segments pre-reading ability, ensure mold base in high speed cutting curve corner position will not appear over-cut, surface over-cut amount measured lower than 0.003mm.

Machine controller internal integrated post-processing algorithm writes P20 steel's cutting compensation value into variables. Processing 500mmx400mm specification template, through NC program auto calling diameter 32mm fly cutter perform face milling, feed rate set at per minute 1500mm.

Program segment internal embedded tool life management system, when milling path cumulative reaches 1200 meters auto triggers alarm. This time operator through 24-station BT50 tool magazine execute 1.8 second rapid tool change, ensure finishing surface brightness Ra value always better than 0.6 micron.

Spindle center water system in drilling 45# steel guide pillar hole provides 2.0MPa constant pressure. Chips are coolant flushed away from hole depth, 20mm diameter deep hole processing efficiency than ordinary cooling way improved 40%. Drill bit each rev feed amount maintain at 0.15mm, hole wall roughness reaches Ra 1.6 micron level.

· Tool path step control: 0.05mm to 0.1mm interval

· Spindle thermal compensation frequency: Every 30 minutes execute once algorithm correction

· G code execution resolution: 1 micron instruction level

· Three axis linkage interpolation error: Plus or minus 0.002mm within

· P20 steel fine milling feed speed: 800-1200mm/min

· Tool holder dynamic balance precision: G2.5/20000RPM standard

· Program pre-processing segment count: 2000 segments preview

Boring program executes G85 command complete guide pillar hole finishing, tool speed locked at 600RPM. Boring head through fine-adjust screw adjust, each small grid represents 0.002mm diameter increment. Measured hole diameter tolerance conforms H7 standard, for 30mm hole diameter its positive deviation range locked at 0 to 0.021mm.

M16 thread hole lead error controlled within 0.02mm. Operator use standard plug gauge on 45# steel mold base perform random check, stop gauge entering amount insufficient 1.5 revs, proves thread pitch diameter consistency reaching standard.

Mold base parting surface sealing groove processing adopts diameter 6mm flat-bottom milling cutter. In CAM strategy select down milling mode, lateral cutting depth maintain at 1.5mm, guaranteed groove bottom and side wall verticality error lower than 0.01mm, eliminated subsequent rubber sealing strip installation after leak hazard.

Probe touches P20 template benchmark surface, repeat measurement precision reaches 0.001mm. Scanning data real-time feedback to machine tool coordinate system, if discover workpiece because clamping stress generate 0.015mm deformation, system will auto trim subsequent trajectory.

Aimed at diagonal length 600mm mold base, two holes center distance measured deviation in plus or minus 0.012mm. This detection mechanism replaced traditional offline measurement, single template quality inspection time from 45 minutes shortened to 8 minutes.

· Probe signal transmission way: Infrared 360 degree sensing

· Online detection repeat precision: 0.001mm

· Coordinate system auto compensation threshold: 0.01mm

· Probe needle ball diameter tolerance: Plus or minus 0.0005mm

· Measurement data upload protocol: Ethernet/RS232 interface

· Environment temperature auto correction coefficient: 12.8 micron/meter/degree

· Edge finding centering time: Single point collection smaller than 3 seconds

Aimed at P20 material in processing generated cutting heat, spindle constant temperature chiller unit presses oil temperature fluctuation within 1 degree Celsius. This prevents spindle axial generating exceeding 5 micron thermal extension. Measured deep cavity mold bottom flatness, in 400mm range deviation only is 0.008mm.

45# steel template water transport hole adopts U-drill high speed processing, cutting speed (Vc) reaches 180m/min. U-drill non-symmetric blade layout eliminated drilling starting stage transverse edge deflection. Measured 300mm depth water transport hole, its exit position deviation controlled within 0.4mm, guarantee not interfere ejector hole position.

Machine equipped laser tool setter after tool cutting 30 minutes auto detect length loss. If tool tip wear exceeds 0.02mm, system auto updates tool offset value. This guaranteed in processing multiple sets P20 templates, each plate piece between cavity depth maintains high degree consistency.

45 degree chamfer edge width set as 0.5mm, measured uniformity deviation in 0.05mm range. Operator use specialized gauge check template thickness, 200mm thickness steel plate, parallelism error locked in 0.015mm.

All connection bolt holes on vertical machining center one-stop complete drill, expand, boring processes. 45# steel surface processing texture presents uniform grid shape, naked eye observation no obvious vibration waves. Use microscope enlarge 50 times observe, tool tip cutting edge left join marks height difference lower than 3 micron.

· Finished mold base flatness: 0.012mm / 500mm

· Side wall verticality: 0.01mm / 100mm

· Mold base mold-clamping gap: Smaller than 0.02mm

· Thread hole center distance tolerance: Plus or minus 0.02mm

· Guide pillar hole cylindricity: Within 0.005mm

· P20 steel surface roughness: Ra 0.45um

· 45# steel plate edge thickness consistency: Plus or minus 0.01mm

Auto lubrication system every 20 minutes to lead screw and rail inject 3ml liquid oil. High concentration emulsion maintain at 8% around, inhibited processing 45# steel when built-up edge generation. Spindle load meter in processing P20 when shows as rated power 35%, guaranteed machine tool in 24 hours continuous operation under thermal stability.