A kind of powdering quality control method and increasing material manufacturing equipment
The invention belongs to increases material manufacturing technology field, and in particular to a kind of powdering quality control method, a kind of paving is further related to
The increasing material manufacturing equipment of powder forming quality.
Increases material manufacturing technology is based on three-dimensional CAD model data, by way of increasing material and successively manufacturing, with computer
Three Dimensional Design Model is source, by software hierarchy and numerical control formation system, is successively piled up material using high energy beam, most
Whole superposition forming, produces a kind of technological means of geometry in particular part.The process of increasing material manufacturing has many kinds,
It is broadly divided into the manufacture method based on automatic powder feeding system and based on powdering mode.The laying formed powder that power spreading device moves in circles,
With reference to the continuous decline and the scanning shaping of high energy beam of forming platform, shaping 3 d part is gradually stacked.
Power spreading device during powdering, can because the unstability of recyclegas, the low precision of forming platform, into parameter
The reasons such as several imperfect, scraper scratch formation of parts, cause power spreading device during the powdering for moving in circles, formed powder
Fail that shaped region is completely covered, in turn result in the situation for occurring constantly repeating shaping scanning in the region of formation of parts, so that
The quality of formation of parts is influenceed, when situation is serious, or even the failure that the scanning shaping of formation of parts can be caused.In existing scanning
In forming technique, increasing material manufacturing equipment cannot real-time monitoring powdering quality, cannot timely be found when above-mentioned situation and
During treatment, it is possible to the problem of the scanning forming quality for influenceing formation of parts occur.
The content of the invention
It is an object of the invention to provide a kind of powdering quality control method, powdering quality is carried out after every layer of powdering terminates
Monitoring, solve the problems, such as existing powdering method cannot real-time monitoring powdering process and powdering quality.
It is a further object to provide a kind of increasing material manufacturing equipment for monitoring powdering quality.
A technical scheme of the present invention is, a kind of powdering quality control method, after the completion of current layer powdering,
The photo of shaped region is shot by being arranged on the video camera above forming platform, the whole shaping covered by formed powder is obtained
The overall intensity value information of platform, if the difference of the gray value and gray threshold set in advance is in the range of error permission,
Then powdering success, if in the range of error permission, increasing material manufacturing equipment stops powdering work.
Further, the method is comprised the following steps：
Step 1, obtains current tomographic image
After the completion of the laying of current layer powder, the photo in forming platform region is shot by video camera；
Step 2, current layer image procossing
Maximum between-cluster variance image segmentation algorithm based on genetic algorithm carries out image segmentation treatment to the photo for shooting, and
Obtain the overall gray value A in forming platform region；Forming platform is laid using similar formed powder, and carries out many experiments, by
Camera acquisition powder lays photo when successfully, calculates its average gray value, is defined as average gray threshold value B；
Step 3, judge whether powdering succeeds
If the difference of overall gray value A and average gray threshold value B is in the range of error permission, powdering success is judged,
Increasing material manufacturing equipment continues executing with the work of shaping scanning；Otherwise, judge that powdering fails, increasing material manufacturing equipment stop it is corresponding into
Shape scanning work, treats the complete failure of artificial treatment, then the work for starting shaping scanning.
In order to determine whether the reason for powdering fails, when the difference of overall gray value A and average gray threshold value B is beyond mistake
During the scope that difference is allowed, the gray value abnormal area for shooting forming platform region in photo is extracted, and by the gray value exceptions area
The gray threshold in domain is defined as C, and the gray threshold C of gray value abnormal area is compared with average gray threshold value B, judges paving
The reason for powder fails：
If C is less than B, powdering is probably unsuccessfully because the reasons such as bulky grain attachment, scraper scratch part cause, it is also possible to
It is that powder causes less；
If C is more than B, powdering is unsuccessfully because accumulated powder excessively causes in doctor blade holder powder falling groove.
The extraction of above-mentioned gray value abnormal area uses gray level threshold segmentation method.
Another technical scheme of the present invention is that a kind of increasing material manufacturing equipment for monitoring powdering quality is wrapped
The filming apparatus positioned at forming platform overlying regions are included, filming apparatus are connected with computer.
Further, filming apparatus are video camera.
The beneficial effects of the invention are as follows monitoring method of the invention can carry out monitor in real time to powdering quality, with convenient to operate
Personnel understand powdering quality condition at any time, pinpoint the problems in time, slacken or even eliminate because cannot real-time monitoring powdering process
And the quality of powdering, the problems such as the powdering that causes is of poor quality, part shaping fails.
Brief description of the drawings
Fig. 1 is the structural representation of the increasing material manufacturing equipment of present invention monitoring powdering quality；
Fig. 2 is the principle flow chart of powdering quality control method of the present invention.
In figure, 1. working chamber's plane, 2. video camera, 3. industrial computer, 4. powdering plane, 5. camera acquisition formed image area
Domain, 6. scraper.
The present invention is described in further detail with reference to the accompanying drawings and detailed description, but the present invention is not limited to
These implementation methods.
Device used in the present invention in the top centre position of working chamber's plane 1 as shown in figure 1, be provided with a shooting
Machine 2, video camera 2 is connected by the industrial computer 3 with control shaping.The formed image region 5 that video camera 2 can be collected is comprising whole
Individual powdering plane 4.
After the completion of current layer powdering, the photo of shaped region is shot by video camera, obtain what is covered by formed powder
The overall intensity value information of whole forming platform, if the difference of the gray value and gray threshold is in the range of the Δ that error is allowed,
Then powdering success, if it is not, increasing material manufacturing equipment stops powdering work.
The method according to following steps as shown in Fig. 2 specifically implement：
Step 1, obtains current tomographic image
Scanned through after one layer in shaping, scraper 6 starts to lay next layer of formed powder, after the completion for the treatment of powdering, by taking the photograph
Camera shoots the photo in forming platform region.
Step 2, current layer image procossing
It is carried out into image segmentation treatment by the corresponding Image Information Processing software being pre-installed on industrial computer, and
Obtain gray value information.The image Segmentation Technology uses the maximum between-cluster variance image segmentation algorithm based on genetic algorithm.
Its splitting speed is fast, and contour area segmentation is obvious, and segmentation quality is high, can preferably reach expected image segmentation purpose.
Assuming that being A by the overall gray value in the forming platform region of the photo of shot by camera, and it is sent to meter
In calculation machine.Forming platform is laid using similar formed powder, and carries out many experiments, when being laid successfully by camera acquisition powder
Photo, calculate its average gray value, be defined as average gray threshold value B, and store in a computer.
The derivation of equation of maximum between-cluster variance (OTSU) is as follows：
Note t is the segmentation threshold of prospect and background, and prospect points account for image scaled for w0, and average gray is u0；Background dot
Number accounts for image scaled for w1, and average gray is u1.
Then the overall average gray scale of image is：U=w0*u0+w1*u1
The variance of foreground and background image：G=w0* (u0-u) * (u0-u)+w1* (u1-u) (u1-u), this formula is variance
When variance g is maximum, it is believed that now foreground and background difference is maximum, and gray scale t now is that optimal threshold is
Step 3, judge whether powdering succeeds
If by the overall gray value A and average gray threshold value B in forming platform region in the photo of shot by camera
Difference judges powdering success in the range of the Δ that error is allowed, and increasing material manufacturing equipment then continues executing with the work of shaping scanning.It is no
Then, judge that powdering fails, increasing material manufacturing equipment will send corresponding alarm, fix tentatively or stop corresponding shaping scanning work,
The complete failure of artificial treatment is treated, is eliminated after alarm, can just start again at the work of shaping scanning.
In order to determine whether the reason for powdering fails, when the difference for overall gray value A and average gray threshold value B occur not
When in the range of the Δ that error is allowed, it is possible to use gray threshold segmentation algorithm, forming platform region in extraction shooting photo
Gray value abnormal area, and the gray threshold of the gray value abnormal area is defined as C, it is sent in computer.
The gray threshold C of gray value abnormal area is compared with average gray threshold value B：
(1) if C is less than B.
A) this gray scale abnormal area may be or belt-like zone continuously or discontinuously that thus can determine whether, this kind of situation is big
The reasons such as particle attachment, scraper scratch part cause.When this happens, it is necessary to human intervention, after ability after Resolving probiems
The work of scanning can again be formed.
B) this gray scale abnormal area is likely to be sheet region continuously or discontinuously that thus can determine whether, this kind of situation is powder
Cause less.When this happens, upper computer software needs the deposit in time to formed powder in powder falling bucket to judge, enters one
Step confirms whether the deposit of formed powder is sufficient, if deposit is sufficient, that should be just dust feeder exception.If formed powder
Deposit be not enough to support ensuing shaping scanning work, the shaping scanning work of increasing material manufacturing equipment equally can be whole
No matter which kind of problem of both the above situation is occurred, and error message can be sent to upper computer software by PLC, upper
Machine software can further eject error, possible error reason and corresponding treatment advice be pointed out, to help increase material system
Manufacturing apparatus operating personnel investigate problem, solve failure.
(2) if C is more than B.
This kind of reason is that accumulated powder is excessive in doctor blade holder powder falling groove, causes the formed powder of shaping scanning current layer laying to exceed
Default shaping thickness.When this occurs, warning message can be sent to upper computer software, upper computer software by PLC
Alert window can be equally ejected, to point out current alarm situations, is treated after the completion of current layer shaping scanning, upper computer software can be certainly
It is dynamic that halted state is entered into by working condition, at this time, it may be necessary to human intervention, i.e., by the manual clear powder of increasing material manufacturing equipment operator
And powder falling again, and the powder falling amount of automatic mode is adjusted, so that increasing material manufacturing equipment can preferably will shaping scanning work
After Chu Liwan failures, eliminate warning message after, powdering and using the inventive method powdering quality is entered again again
Row monitoring, until powdering success, then the shaping scanning work for carrying out next layer.