Chart 1

Because the electronic imitating processing method precision is not high, therefore processes the wheel rim roller face shape is worse. Moreover the engine bed movement control aspect uses the old style relay electric circuit control, the electric circuit complex, the failure rate is high, has brought the certain difficulty to the service. Along with our country railroad enterprise development, for adapts the railroad implementation to raise fast and the development high speed train need, the wheel wheel rim roller face manufacture precision and �?repairs the standard more and more high, but original already by far could not satisfy the precision request with the imitating method processing wheel, was satisfies this request to this engine bed implementation numerical control transformation to be most economical, the most effective method. In the recent two years, various railroad car section and the wheel shop carry on the numerical control transformation in abundance to its original C8011B wheel lathe, we in use Simens's 802 series numerical controls system for this engine bed transformation process in, successively has used Simens's 802S, 802C, the 802D numerical control system, among, uses the 802D numerical control system the equipment to transform the plan comparatively to have the typical nature.

When chooses the equipment the transformation plan, first needs to consider is satisfies several requests which the transformation must achieve: 1st, the tool rest X axis and the Z axis control changes by originally the imitating control by the digital axis controls. 2nd, controls original engine bed all movements by the original relay electric circuit control changes the PLC control. After 3rd, the cutting roller face shape satisfies the precision request, the concurrent operation is as far as possible simple.

Above in order to satisfy the condition, we have selected Simens's 802D numerical control system, this system is the digitized numerical control system which the siemens promoted in recent years, in its lathe version standard disposition brought a PP72/48 template, was allowed to realize 72 inputs and 48 outputs PLC controls, simultaneously actuated the module is a two axle power module, was allowed to bring two linear axis and a main axle, in has set at the velocity feedback and the displacement feedback sensor in the servo electrical machinery may form a half closed-loop control system with the main engine thus to be able together to achieve the very high engine bed precision. Moreover the price is moderate, has the very high natural price compared to, may the very good satisfied equipment numerical control transformation request.

Because the C8011B wheel lathe uses two tool rests gets a light from another light the wheel to the about roller face also to process about, therefore we used two set of 802D system separately to control the tool rest movement. But engine bed all movements control then completely control unit controls by left tool rest 802D the system PLC. Left side the 802D system main hardware disposition is:

1st, PCU main engine 1

2nd, entire function vertical keyboard 1

3rd, PP72/48 template 1

4th, 611UE actuation power source 5KW 1

5th, 611UE two axle closed-loop control unit 1

6th, 611UE two axle power module 1

7th, 1FK6 electrical machinery 3000RPM18NM 2

8th, outside meets 2500P/ to revolve encoder 1

9th, tie cable and PROFIBUS data bus certain

About two sides systems hardware disposition is same, uses a SIMODRIVE611UE two axle control module to control two servo electrical machinery separately to actuate X axis tool rest and the Z axis tool rest. Right flank the systematic PLC unit only processes system itself the PLC instruction. But MCP (engine bed control panel) then with the engine bed movement button kneading board integrates in together self-restraint.

In the hardware disposition, we selected beside standard disposition outside to meet revolve the encoder, selected the reason as follows:

Because the numerical control transformation condition limits, although we the original X axis and the Z axis lead screw changed into the ball bearing lead screw, but the middle transmission system still for the old transmission system, led X axis and in the Z axis 滑台 transmission process in the servo electrical machinery, X axis and Z axis transmission structure like chart 2 showed:

Chart 2

By on chart obviously, said regarding X axis, because the gear drive progression are not many, the transmission gap is not big, therefore may use the velocity feedback and the displacement feedback which in the standard disposition use servo electrical machinery sets, this time X axis 滑台 the movement precision also can answer the purpose. But said regarding the Z axis that, the transmission progression are many, moreover also has two levels of bevel gears transmissions, therefore transmission gap big increase, if we still used the servo electrical machinery end displacement feedback, then the Z axis 滑台 the movement precision could not obtain the safeguard. The solution method although has very much, for instance the gearshift transmission perhaps installs diffraction grating ruler and so on, on the Z axis guide rail but because the condition limits with reason and so on price all is not very good solution. Regarding this peculiar circumstance, in order to solve this problem, finally we considered used outside the one has met in the Z axis ball bearing lead screw end connection revolves the encoder means, connection method like chart 3.

Chart 3

This time the Z axis displacement feedback signal direct examination is the Z axis ball bearing lead screw end displacement signal, but the electrical machinery and between the ball bearing lead screw the gear drive transmission gap is all contained in has shut in the endless chain, therefore the Z axis 滑台 movement precision obtained the very big enhancement, has satisfied the precision request.

But in the 802D system actuation disposition, in the line profile shaft control connection has not certainly looked like 802S or the 802C system equally has a special encoder connection, it only has two receives electrical machinery feedback signal X412 and the X411 connection. How this time Z axis does outside meet the encoder the signal to be supposed to connect? On the 611UE two axle closed-loop control unit, we saw has a X472 connection, this connection is uses for to receive the main axle the encoder signal, but certainly does not have in ours numerical control transformation as usefully as the main axle control, therefore we was allowed to use this connection after the revision system interior parameter to accept the Z axis outside to meet the encoder feedback signal. After outside will meet the encoder tie cable like chart 3 the connection, we will only need to revise the 802D system interior in the system data and the two axle power module actuation data outside, set at in the Z axis servo electrical machinery the displacement feedback signal shield to use meets the encoder the feedback signal to be allowed.

This kind meets the encoder outside the ball bearing lead screw end installment the method installment conveniently, increase cost not many but use effect very good, therefore the natural price is extremely higher than. Needs to pay attention only is in installs in the debugging process to want the careful establishment related engine bed data.

Regarding original engine bed black-white control electric circuit transformation, although the engine bed movement certainly is not very many, but controls complex, between the movement security lock are mutually more, therefore appears in the original electricity cabinet electric circuit extremely complex, but completely changed into after 802D the system PLC unit control, the external control electric circuit obtained the enormous simplification. 802D in the system standard disposition PP72/48 template can provide 72 entrance points and 48 outputs spots, the input output enough engine bed use, does not need likely other some numerical controls system such to have extra to increase a I/O input output module.

In in the numerical control processing procedure establishment, 802D uses is the numerical control system general G code programming. Procedure succinct, in this engine bed programming, because processes the roller face shape precision request is higher, moreover also set the very high request to the operation simple user, therefore we has specially considered this point in the procedure establishment. Like chart 1 shows, because processes turn uses to the time operator is the diameter survey, but in ordinary circumstances we when lathe machining programming 进刀 is uses the relative coordinates in X axis direction the way perhaps the hypothesis engine bed work piece coordinates, adopts a zero displacement the method to carry on the processing, but certainly is not suitable in this engine bed. In order to simplify the operation, we used Simens in the system R parameter to establish the cutting quantity, in procedure after corresponding R parameter programming, operator when processing only had the wheel which the input had to process in the R parameter to the diameter value, then the procedure could automatically trade figures out the cutting quantity and carries on the cutting, enormous convenience operation.

Moreover because turn is stricter after the about diameter of wheel processing size request, after processing about turn 径差 cannot be bigger than 0.5mm. Therefore we initial established in the R parameter to adjust the cutting datum to the knife parameter. Changes when the cutter bar length or the numerical control system reference point may extremely quickly facilitate the revision datum, causes the wheel which the input the diameter value and actually cuts to the diameter value to maintain completely consistently.

Also some point is when the cutting turn to, regarding other numerical control systems, the Z axis direction usual operator in the inside after the knife needs in the Z axis current coordinate figure input parameter, but in the 802D numerical control system may read takes the current coordinate figure the function to be allowed to cause the operator not to use the data-in, we only must increase "r0=$AA-IM after the processing procedure [ Z>", the system may directly read in the current Z axis coordinate figure to R parameter R0 in, such operator when operation on only needed to input each shaft coupling to the diameter of wheel value which had to process to be allowed directly to process, extremely simple was convenient.

In in an equipment numerical control transformation process, the electronmagetic interference phenomenon always is in installs debugs in the scene frequently to puzzle debugs personnel's very major problem, because uses the old equipment the workshop and the location generally speaking working conditions quite bad, 强干�?source many, moreover the electrical network voltage undulation is bigger, the zero curve, the grounding quality are not very high, therefore frequently bumps into the disturbance phenomenon in the debugging process. For the interference elimination, designs and debugs the personnel to be able not but to pay the extra very many energy. Below for example we once used other systems in to carry on the numerical control transformation in the wheel lathe to encounter the situation: Usually the numerical control system all works normally, every day but always has 12 times of numerical controls systems suddenly anxiously to stop in the work, screen visual display alarm is X axis encoder hardware breakdown, after on again the electricity the engine bed restores normally, regarding this we start to suspect is moves the encoder damage perhaps the line contact is not good, but looked up the very long time, took very many measures all not to be able to eliminate this phenomenon the production, the final inspection result determination was the system has received the workshop voltage instantaneous undulation disturbance, afterwards could not but enter the terminal in the equipment power source to install a voltage stabilizing transformer, And alone has installed a quality very good grounding. Although finally has solved the problem, but has wasted the very much time and the energy. After has used Simens's 802D system, because this system has adopted the current extremely popular use Profibus data bus each function module connected communication way, therefore not only the structure is simple, moreover the anti-jamming big increase, reduced the numerical control equipment to have each kind of unclear breakdown phenomenon possibility because of the electronmagetic interference.

Has carried on the numerical control transformation in us to the railroad system many units' C8011B wheel lathe after Simens's 802D numerical control system, after the transformation engine bed performance reliable, the processing precision high, the operation simple, the maintenance is convenient, therefore obtained user's widespread approval and highly appraises.