Module 3 Flashcards
Describe the design approach during the case study.
1) The system level options.
2) Materials and processes. Here the materials and processes trade-off happens.
3) Structural design, with a FEM model and a mass estimation.
4) Thermal accomodation. A thermal analysis is conducted and the mass and powder is estimated. This is an iterative step with step 3.
5) Programmatics/AIV (assembly, integration and verification)/Cost/Risk. Here the risk is identified (impact and likelihood), the schedule impact and the cost impact. This is an iterative step with step 2.
6) Mass and power budget. The budget is compared with the current baseline design.
What was the process for evaluating the potential benefits of a designed combination of AM technology, materials and applications for future launchers and next generation of space hardware?
1) Phase 1: Screening for target application and review fo potential ALM technologies.
2) Phase 2: Definition of development and verification plan. Mechanical characterization and advanced NDT. (static, fatigue, microstructure tomography, UT, eddy currents, etc.).
3) Execution fo TVDP. Materials and demonstrators.
4) Preliminary breadboard definition and topology optimization.
5) Manufacturing and verification.
Phase 1: Screening for target application and review fo potential ALM technologies.
- Perform a screen of state-of-the-art for ALM studying of principles, classification, relationships among processes, materials, SW, quality control and application of ALM technologies at a more systematic level. Cometitivness factors: advantages and drawbacks.
- Perform a trade-off between materials, manufacturing process and technical requirements associated with the technology & faclities selection.
- Screening for target application for launchers. Identifying the components that can be manufactured with ALM technologies, including the identification of critical parts location, functional requirements design, manufacturing tech. cost & lead times, etc. and performing an ALM technology assessment identifying the driving factors.
What does the AM definition phase contain?
1) Functional requirements:
- Leak,burst.
- Required mechanical properties.
- Structural analysis.
2) Definition of AM design constraints:
- Build envelope
- Machine-material link
- Inspectability
-Design rules
3) Criticality-assessment of AM process
- Properties of selected material
- Acceptance criteria for defects
- Achievability of cleanliness requirements for selected application.
4) Definition of porst-processing techniques:
- Suitability for selected material, design,e tc.
- Machining (eg. milling, turning, ..)
5) Suitability of NDI techniques.
- Detection limits that match acceptance criteria.
All these consist the definition of AM end to end process and leads to the Preliminary Manufacturing Concept Review (PCMR).
What are some AM processing issues in the technology screening?
1) Parameters:
- Laser power
- Fous offset
- Exposure time
- Point distance
- Hatch distance
- Scanning path
2) Porous/low-dense material
3) Parts positioning
What are some AM considerations for post-processing?
1) Removing material
2) Release of internal stresses
What are some AM considerations for NDI methods?
1) Conventional techniques (eg ultrasound, eddy current, liquid penetrant inspection, radiographic inspection) to measure crack-like defects.
2) Advanced techniques (eg X-Ray computer tomography) to measure volumetric defects (eg voids, pores).
What are some AM considerations for performance?
Advantages:
1) Tool reduction. The part is obtained directly from a 3D Cad model. It becomes viable to redesign and produce improved parts without manufacturing new tooling components.
2) Material is added and not substtracted - less waste and less use of raw materials.
3) Geometric flexibility. ALM allows for geometric complexity and manufacturing of components that cannot be made by traditional methods.
4) Freedom design.
5) Part consolidation.
6) Time saving.
7) Cost efficiency.
8) Carbon foot print reduction. Due to reducing raw material and energy for each part produced + weight in transporting.
Drawbacks:
1) Post processing. Usually needed to remove material support after manufacturing and machining for better surface finishing.
2) Size limited. Increasing size usually leads to increase lead time and reduces accuracy.
3) Design aspects. Part orientation will impact on surface quality, build time and part cost.
4) Process variance. The final part depends on a large number of parameters, such as build speed or part orientation and this variance affects the material properties of the part.
5) Surface finish/part accuracy.
6) Low volume deuction. For high volume quantities, moulding and casting are still preffered.
7) Lack of process standards. Currently, for each part it is needed a specific analysis in order to calibrate the machine and optimize the process parameters.
What are some AM considerations for the cost analysis?
1) Facility costs
2) Material and ancillary costs
3) Labour coss
4) Other costs
What are some AM considerations for competitiveness factors?
1) Cost. Cost is the most oundstanding competitiveness factor. It is influenced by a wide range of factors, amogn which only a few are important for ALM processes: material savings, reduction of lead time, no toolling needed.
2) Quality. Good surface finish and high accuracy parts are needed. Currently post-processing is needed by machining the parts.
3) Performance. Increased strength to weight ratios.
4) Flexibility. Design freedom with frew constraint.
5) Innovation.
6) Size. Currently, most ALM methods only provide a small build volume and this is a challenge.
Phase 2: Definition of development and verification plan. Mechanical
1) Preparation and confirmation of feasibility of the manfacturing process before these are applied to fabricate a dmonstration structure
2) Verification of the manufacturing capabilities through speciments and test articles.
3) Preparation of the development test and subsequent execute.
4) Preparation and confirmation of feasibility of inspection process, specially NDI, before these are applied to a demonstration structure
5) Increase TRL (technology readiness level) value of each individual manufacturing operation to achieve a TRL 4 for the ALM process at the end of the activity.
What are the objectives of the manufacturing parameters investigation?
1) Technology consolidaton by understanding the manufacturing process and involved materials.
2) Understanding the effects of different parameters on materials microstructure (laser path, porosity and pore distribution)
3) Understanding the relationship between parameters and developed microstructure.
4) Estabilishing highly optimized/high dense processing parameters for different alloys.
5) Determination of static/fatigue mechanical properties of high dense samples with optimized parameters.
6) Study of the surface finsihing treatments and its improvement methods.
7) Assessment of the boundaries for the SLM technology to transfer the knowledge to the next level.
Describe the AM Pre-verification phase.
1) Analysis of powder feedstock
2) Definition of operation parameters:
- Shielding methods/gas
- Energy input
3) Estabilish working process window:
- Cubes for density measurement
- Tensile testing for design values
4) Establish process windows for post processing for:
-reducing surface roughness
- heat treatment. This is iterative with step 2.
5) Select NDI Techniques that can detect unacceptable defetcs (eg pores, cracks, lack of fusion).
6) Preliminary Additive Manufacturing specification (pAMS).
7) Prellinary Manufacturing Review and PDR
8) Additive manufacturing verification test plan to verify:
i) On standard test samples
- Mechanical properties
- Microstructures
ii On specific, representative features of the inteded product to:
- Producibility
- Possibility to remove powder
- Effectiveness of post-processing methods (eg for required surface roughness, cleaninliness, etc)
- Feasibility of chosen NDI standards
9) Production of samples or features.
10) Test campaign according to AMVTP
- First build inspection
11) Issue Additive Manufacturing Procedure Specification (AMPS) and test report
- Critical manufacturing review (CMR) and CDR and MRR
