Why is it necessary to conduct DFM process review before the five axis production of robot shaped parts processing?

Engineers who outsource robot components are likely to have encountered a situation  all 3D simulations have passed,  the various indicators on the drawings look reasonable,  are directly sent to the processing plant for installation. When the parts returned, it was discovered that the thin-walled position was deformed, the internal corners were  in place,  some characteristic tools could  cut at all. So the project was reworked, redesigned,  put back  production,  the project schedule was directly disrupted. Many people think that the five axis machine tool has insufficient capabilities, but in reality, many problems have already been hidden in the drawing stage,  there is a lack of DFM process investigation before production.  

The structure of ordinary standard parts is simple, with conventional three-axis machining,  stable output without complex evaluation. However, high difficulty workpieces such as robot joint shells, dexterous hand components,  aerospace thin-walled supports are mixed with a large number of thin-walled suspensions, multiple intersecting curved surfaces,  multi angle oblique holes. The majority of processing factories on the market adopt a "direct processing according to drawings" model  do  proactively conduct systematic risk assessments. The unreasonable structure, strict but unnecessary tolerances, missing clamping benchmarks,  post-processing dimension offset issues inherent in the drawings are all left exposed in the machining process. Finally, it leads to scrap  rework, increases the cost of R&D trial  error,  slows down the pace of iteration. This is also the reason why high-end irregular parts processing  DFM pre evaluation are increasingly valued.

Distinguishing: General DFM ≠ Five axis CNC Parts Exclusive DFM Review

Many DFM content online tends to focus on the mass production design logic of injection molding  die-casting molds. The DFM review logic for non-standard robot parts is  the same. Its starting point is  to modify the core functions of the product, but based on the practical conditions of five axis linkage equipment capability, non-standard thin-walled structure,  small batch iteration of research  development, to identify the risks of processing implementation. Resolve the practical contradiction of "simulation design is feasible, but it is difficult to do on the computer  batch production is unstable". Taking the multiple dexterous hand skeleton projects processed by Shenzhen Huiwen Zhizao as an example, during the review process, the core assembly dimensions of the finger joints will  be changed, only suggestions will be given for the R angle of the adapter, process landing, non critical position tolerances,  anodizing compensation, while reducing the probability of processing scrap without changing the overall performance of the machine.  

Five axis DFM review, focusing on identifying several types of on-site risks

1. Structural Machinability: Identify tool interference  cutting blind spots

Robot parts often exhibit features such as deep cavities, narrow grooves, undersized inner R,  inverted buckles. Even with five axes, there is a risk of tool interference. During the review phase, check the 3D model one by one to identify cavity positions that are too large in length to diameter ratio, have narrow interior angles,  cannot be reached by the tool; Provide suggestions for optimizing rounded corners, adding process holes,  locally splitting processes to avoid discovering cutting dead corners only after installation.  

2. Risk assessment of thin-walled deformation: predicting rebound caused by clamping  cutting

Thin walled  suspended structures are the most prone areas for robot parts to overturn. Aluminum alloy  titanium alloy have poor rigidity in thin-walled areas,  clamping forces  cutting vibrations can cause elastic deformation. The DFM process evaluates the weak positions of parts, predicts the clamping force points,  plans in advance for the entire process route of contour support, separation of rough  fine machining,  stress release, in order to reduce on-site failures  the source of "qualified clamping but out of tolerance when loosened".  

3. Tolerance  benchmark sorting: avoid yield loss caused by the superposition of multiple tolerances

Some drawings may have extremely high tolerances marked in non appearance positions; Inconsistent design  processing standards; Double tightening of positional  aperture tolerances. When evaluating, distinguish which dimensions must be strictly adhered to for core assembly  which are non critical positions for appearance. Communicate with R&D to moderately loosen redundant  strict tolerances while maintaining performance,  unify the entire benchmark system to reduce chain errors caused by benchmark conversion.  

4. Material  post-processing link evaluation: Reserve size compensation in advance

The cutting characteristics of 7075 aluminum alloy, TC4 titanium alloy,  PEEK materials vary greatly; Anodizing  passivation can also cause changes in film thickness. If there is no reserved compensation during the processing stage  all CNC measurements are qualified, the surface treatment will result in assembly failure. DFM review needs to combine the selection of materials for parts, predict the size changes of the entire process chain,  reserve allowances in advance.  

5. Consider the transferability of prototype iteration to small batches

Many prototypes rely on manual adjustment by experienced technicians, without a fixed cutting path  tooling. After several iterations of the drawings, there were quality fluctuations when producing a new batch. DFM review is  just about providing single sample services, but also taking  account subsequent small batches, promoting modular tooling, procedures,  quality inspection standards as much as possible,  reducing the cost of process reset caused by each drawing change.  

The practical value of pre evaluation

Many R&D teams are concerned that DFM reviews may prolong the lead time.  the overall perspective of the project, a review investment of 1-2 working days can avoid several weeks of time spent on later modifications, re cutting,  repeated processing. About 80% of rework  scrap hazards can be identified during the drawing stage. Shenzhen Huiwen Intelligent Manufacturing Technology Co., Ltd. uses DFM as a pre process for five axis machining, relying on ISO9001  IATF16949 quality systems, combined with 370+production testing equipment, to provide process risk control for humanoid robots  aerospace components; After receiving the drawings, conduct a comprehensive risk assessment, output feasible optimization suggestions, adapt to sampling, multiple iterations,  small to medium batch scenarios.  

Frequently Asked Questions

Q1: Do simple standard CNC parts still need to undergo DFM review?

A: Conventional simple flat  standard hole position parts, with mature technology  extremely low risk, do  require special DFM review. DFM front-end risk control mainly targets high difficulty machining categories such as robot shaped parts, thin-walled deep cavity parts, multi surface complex parts, high-precision tolerance components, etc., accurately matching high-end precision machining scenarios.  

Q2: Will DFM review modify product design  affect equipment performance?

A: I won't. The DFM process review of Huiwen Zhizao is based on the premise of "retaining all functional designs", optimizing only the details of the process implementation, such as adjusting the R angle of the adapter, reserving processing compensation, optimizing the clamping position, relaxing non critical tolerances, etc., without changing the core structure, assembly dimensions,  usability of the parts at all.  

Q3: Will the pre DFM review extend the delivery cycle of parts?

A: On the contrary, it significantly shortens the overall project cycle. A single DFM review only takes 1-2 working days, which can completely avoid the long  time-consuming process of rework, drawing modification, scrapping,  reprocessing in the later stage. For high-end R&D projects with frequent iterations  strict accuracy, it is the core means of speeding up  reducing costs.

If you need a precision parts processing plan  quotation, please feel free to provide drawing consultation. We can provide 2D drawings, 3D models,  technical requirements to obtain DFM process evaluation  itemized processing quotations.