CN103753269B - A kind of clamping method that can compensate for sheet member machining deformation - Google Patents

Abstract

The invention particularly discloses a kind of clamping method that can compensate for sheet member machining deformation, including using four supports, each support to support workpiece as a strong point bottom step (1) workpiece, the position relationship of four points is rectangular；(2) being arranged over four pressing plates at workpiece, each pressing plate has two pressure heads, and each pressure head compresses a some workpiece pressing as one；(3) two compress point and are distributed over the strong point both sides of longitudinal direction.Compared with the existing compensation method that workpiece is deformed, use this clamping method clamping to compensate workpiece deformation and will not reduce working (machining) efficiency, and workable.

Description

A kind of clamping method that can compensate for sheet member machining deformation

Technical field

The present invention relates to a kind of clamping method, particularly relate to a kind of cutting force that can automatically adapt to and compensate the clamping side of sheet member deformation Method.

Background technology

Under the effect of cutting force or clamping force, cutter, workpiece it may happen that bigger machining deformation, actual at cutter-contact point are cut Deep more than or less than theoretical value, then produce " cross and cut " or " owing to cut " phenomenon.Especially for thin plate, thin wall component, " crossing and cut " or " owing to cut " phenomenon is serious, generally require and carry out being repeated several times polish, working (machining) efficiency is low, precision is difficult to ensure that Problem ratio more prominent.For this deformation, existing compensation method mainly have amendment cutter feed path (see document " Zhang Pan, Chen Weifang. thin-wall part machining deformation prediction and active compensation method. modern Manufacturing Engineering, 2008,3:70-72 "), optimize cutting Parameter is (see document " M.Wan, W.H.Zhang, G.H.Qin, Z.P.Wang.Strategies for error prediction and error control in peripheral milling of thin-walled workpiece[J],International Journal of Machine Tools and Manufacture, 2008,48, (12-13): 1366-1374 "), cutter beat (Zhao Wei etc., the cutter beat NC compensation process technology of Thin-walled Workpiece. machine-building and research, 2002) etc., but first two Compensation method all can reduce working (machining) efficiency, and the third method is not easily accomplished (generally needing 4～5 Shaft and NC Machining Test lathes to realize) And it is not particularly suited for face milling processing.

When sheet member is cut, frequently with a supporting way clamping, but when using existing common pressing plate, pressing plate Bigger contact surface is had, and owing to contact surface is not absolute plane with workpiece, so thrust on contact surface uneven, Therefore it is likely to result in bigger clamping deformation, in turn results in the machining deformation that workpiece is bigger.When reducing the contact surface of pressing plate and workpiece, Use some a strong point clamping mode clamping (see document " Liu Yumei. sheet member cutting resilience mechanism and clamping optimization method grind Study carefully. Shandong University, 2012 ") time, there is following both sides problem: one be when clamping point and the strong point the most just pair time, then Pressing plate function clamping force on workpiece has functioned only as clamping the effect of workpiece, and clamping force can not be utilized to compensate the processing of workpiece Deformation.Two is when clamping point and the strong point stagger, and pressing plate function clamping force on workpiece can only compensate inside the strong point or outward The deformation of side, and after compensate for the deformation of side, the deformation of opposite side can be bigger.

In actual working angles, cutting force and clamping force are the most all playing negative effect to the machining deformation of workpiece.When Cutting parameter one timing, cutting force is cannot be controlled, but can be by pressing plate and control clamping force.Clamping workpiece completes it After, when the effect that workpiece deformation is played by clamping force is contrary with the effect that workpiece deformation is played by cutting force, just clamping can be utilized The deformation that force compensating cutting force causes.But have not seen the clamping method that can effectively utilize clamping force to compensate workpiece deformation.

Summary of the invention

In order to solve the shortcoming that prior art exists, the invention particularly discloses a kind of clamping that can compensate for sheet member machining deformation Method, utilizes clamping force to compensate the machining deformation that sheet member causes because of cutting force by this clamping method.

The technical solution used in the present invention is as follows:

A kind of clamping method that can compensate for sheet member machining deformation, as follows:

1. using four supports bottom workpiece, each support supports workpiece as a strong point, and the position relationship of four points becomes square Shape；

2. it is arranged over a pressing plate at the workpiece relative with each strong point, bottom each pressing plate, has two pressure heads, each pressure Head compresses some workpiece pressing as one；

3. two compress the point-symmetric strong point both sides being distributed in corresponding thereto.

On Workpiece length direction, owing to the value of each clamping force is continually changing in working angles, compress point so each and prop up In distance between support point and each briquetting, the size of clamping force can obtain by finite element emulation software simulation calculation.To reach phase To preferable compensation effect.After clamping platen, it is ensured that when cutting workpiece, pressing plate does not rotates along with workpiece, to ensure clamping force Towards the Long-term change trend deformed in compensation workpiece effectively in working angles, and then the benefit that workpiece is deformed by this clamping method can be ensured Repay effect.

The invention has the beneficial effects as follows:

Compared with the existing compensation method that workpiece is deformed, use this clamping method clamping to compensate workpiece deformation and will not reduce processing Efficiency, and workable.

Compared with supporting installation way with common point, this clamping method can utilize clamping force to compensate inside the strong point by pressing plate simultaneously With the deformation in outside, and this clamping method can make clamping force adapt to cutting force change from trend facilitate compensating for workpiece deformation Long-term change trend.

Accompanying drawing explanation

The front view of Fig. 1 clamping workpiece；

The side view of Fig. 2 clamping workpiece；

The top view of Fig. 3 clamping workpiece；

Fig. 4 is clamping whole implementation figure；

Fig. 5 is the structure chart of pressing plate；

Force analysis figure when cutting force is on the right side of workpiece under Fig. 6 (a)-Fig. 6 (e) this clamping method；

Under Fig. 7 (a)-Fig. 7 (g) this clamping method cutting force within the workpiece between time force analysis figure.

In figure: 1 support, 2 workpiece, 3 pressure heads, 4 pressing plates, 5 clamp base, 6 alignment pins, 7 bolts.

Detailed description of the invention

The present invention is described in detail below in conjunction with the accompanying drawings:

A kind of clamping method that can compensate for sheet member machining deformation, as follows:

1. using four supports bottom workpiece 2, each support supports workpiece as a strong point, and four positions supporting 1 are closed It is tied to form rectangle；

2. being arranged over four pressing plates 4 at workpiece 2, each pressing plate has two pressure heads 3, and each pressure head compresses point as one Workpiece pressing；

3. two pressure heads 3 are distributed over support 1 both sides of longitudinal direction.

The principle of this method is as follows:

When cutter (screw-on cutter, lower same) moves to workpiece end (such as N position in Fig. 6 a), workpiece is applied by cutter Axial cutting force F can force workpiece generation elastic deformation, with cross strong point surface of the work vertical line (straight dashed line in Fig. 6 a) be Demarcation line, upwarps, away from the side recessed (such as imaginary curve in Fig. 6 a) of cutting force near the side of cutting force.Now fixing pressure Block position, D compresses point will be tightr with absorption surface, it is assumed that acts on the clamping force on whole briquetting constant, then D compresses Point acts on the clamping force on workpiece and increases, and on the contrary, C compresses the clamping force reduction that point acts on workpiece.Workpiece is simplified to Overhanging beam such as Fig. 6 b, under the effect of power F, the amount of deflection of N point is(such as Fig. 6 c).Ignore clamping Power F_A、F_BImpact on N point amount of deflection,

At F_CEffect under, the amount of deflection of N point(such as Fig. 6 d)

At F_DEffect under, the amount of deflection of N point is(such as Fig. 6 e).

According to Superposition Method beam deformation method, the least in flexural deformation, and in the case of material obedience Hooke's law, line of deflection The differential equation is linear, when acting on several load on beam simultaneously, can obtain the deformation that each load individually causes respectively, Gained deformation superposition is deformation when these load act on jointly.Then, combined deflection ω of N point_N2Should be ω₁、ω_C1And ω_D1 Superposition, i.e.

$\begin{array}{c}{\mathrm{\ω}}_{N2}={\mathrm{\ω}}_1+{\mathrm{\ω}}_{C1}+{\mathrm{\ω}}_{D1}=\\ \frac{{\mathrm{Fd}}^2(d+s)}{3\mathrm{EI}}+\frac{F_{C}a(s-a)(s+b)d}{6\mathrm{EIs}}-\frac{F_D\mathrm{asd}}{3\mathrm{EI}}-\frac{F_D{a}^2(3d-a)}{6\mathrm{EI}}---\left(1\right)\end{array}$

At tool motion to workpiece centre position R time (as shown in Figure 7a), the axial cutting force F that workpiece is applied by cutter Also workpiece generation elastic deformation (as shown in dotted line in Fig. 7 a) can be forced.(scheme with the vertical line crossing strong point surface of the work as demarcation line Straight dashed line in 7a), upwarp near the side of cutting force, the side away from cutting force is recessed.Now fix briquetting position, then B, C two compresses point will be tightr with absorption surface, it is assumed that acts on the clamping force on whole briquetting constant, then B, C compress point Acting on the clamping force on workpiece to increase, on the contrary, A, D two compresses the clamping force reduction that point acts on workpiece.By workpiece letter Chemical conversion overhanging beam such as Fig. 7 b.

Under the effect of power F, the amount of deflection of R point is(such as Fig. 7 c)；

At F_AEffect under, the amount of deflection of R point isSuch as Fig. 7 d.

At F_DEffect under, the amount of deflection of R point isSuch as Fig. 7 e.

At F_BEffect under, the amount of deflection of R point is

Such as Fig. 7 f.

At F_CEffect under, the amount of deflection of R point isSuch as Fig. 7 g.

Then, combined deflection ω of R point_R2Should be ω₂、ω_A2、ω_B2、ω_C2And ω_D2Superposition, i.e.

$\begin{array}{c}{\mathrm{\ω}}_{R2}={\mathrm{\ω}}_2+{\mathrm{\ω}}_{A2}+{\mathrm{\ω}}_{B2}+{\mathrm{\ω}}_{C2}+{\mathrm{\ω}}_{D2}\\ =\frac{\mathrm{Fd}(s-d)[s^2-{(s-d)}^2-d^2]}{6\mathrm{EIs}}+\frac{F_{A}a(s-d)d[2s-(s-d)]}{6\mathrm{EIs}}\\ -\frac{F_B\{\frac{s}{b}{[(s-d)-a]}^3+(s^2-b^2)-{(s-d)-(s-d)}^3\}}{6\mathrm{EIs}}\\ -\frac{F_{C}a(s-d)[s^2-{(s-d)}^2-a^2]}{6\mathrm{EIs}}+\frac{F_{D}a(s-d)[s^2-{(s-d)}^2]}{6\mathrm{EIs}}\end{array}---\left(2\right)$

In formula, E is the elastic modelling quantity of workpiece, and I is the moment of inertia of workpiece, and F is axial cutting force, and s is that Workpiece length direction is propped up Distance between support, d is F application point to the distance supported between P, and a is to compress the distance between point and the strong point.F_A、 F_B、F_C、F_DIt is respectively the thrust compressed at some A, B, C, D.

When tool motion to workpiece end, under the effect of cutting force, amount of deflection ω of N point_N1=ω₁.The amount of deflection of N point after compensation For ω_N2=ω₁+ω_C1+ω_D1, compensation dosage is ω_C1+ω_D1, along with F_CReduction, F_DIncrease, then | ω_C1| reduce, | ω_D1| increase, Work as ω_C1+ω_D1< when 0, | ω_N1|>|ω_N2|, i.e. this clamping method can compensate the workpiece deformation that a part causes because of " cross and cut " automatically.

When cutter within the workpiece between position time, under the effect of cutting force, amount of deflection ω of R point_R1=ω₂, the amount of deflection of R point after compensation ω_R2=ω₂+ω_A2+ω_B2+ω_C2+ω_D2, compensation dosage is ω_A2+ω_B2+ω_C2+ω_D2Along with F_A、F_DReduction, F_B、F_CIncrease, Then | ω_A2|、|ω_D2| reduce, | ω_B2|、|ω_C2| increase, work as ω_A2+ω_B2+ω_C2+ω_D2< when 0, | ω_R1|>|ω_R2|, i.e. this clamping method Also the workpiece deformation that a part causes can automatically be compensated because of " cross and cut ".

One clamping example is as follows:

Clamping instance graph such as Fig. 4, whole device is placed in clamp base 5, workpiece use four round head columns as support, three Individual alignment pin 6 positions, and each supports a corresponding pressing plate (such as Fig. 5), and each pressing plate is provided with two pressure heads as compressing point, On Workpiece length direction, two compress point and are distributed in both sides for the corresponding strong point, the most each compress between point and the strong point away from From and each briquetting on the size of clamping force can obtain by finite element emulation software simulation calculation.By tightening the bolt on pressing plate 7 apply clamping force, and clamping completes.

Claims (1)

1. the clamping method that can compensate for sheet member machining deformation, it is characterised in that as follows:

(1) sheet member, support, pressure head, pressing plate, alignment pin and bolt are both placed in clamp base, use four bottom sheet member Individual round head column is as support, and three alignment pin location, each support supports sheet member as a strong point, and the position of four points is closed It is tied to form rectangle；

(2) it is arranged over a pressing plate in the sheet member relative with each strong point, bottom each pressing plate, has two pressure heads, each Pressure head compresses point as one and compresses sheet member；

(3) on sheet member length direction, two compress the point-symmetric strong point both sides being distributed in corresponding thereto；

(4) by tightening the bolt applying clamping force on pressing plate, clamping completes.