Please only respond if you or someone you know specifically makes custom, rounded domes.
I'm replying even though I don't meet this requirement!
You should be aware of the industrial production process for polycarbonate light domes:
First of all, you need the mold.
Production of forming tools for the thermoforming of rooflights:
1. design and construction:
CAD development:
Creation of a 3D model of the desired rooflight shape
Consideration of draft angles (at least 3-5°)
Integration of ventilation channels for vacuum/compressed air
Calculation of the material distribution during the forming process
Simulation of the thermoforming process to optimize the tool geometry
Special design features:
Allowance for shrinkage (approx. 0.5-0.8% for polycarbonate)
Design of cooling channels for even temperature distribution
Integration of measuring points for temperature sensors
Design of clamping fixtures and holders
2. material selection for the forming tool:
Requirements:
Temperature resistance up to 200°C
High thermal conductivity for fast cooling cycles
Good machinability for precise surfaces
Long-term stability against wear
Typical materials:
Aluminum alloys (e.g. EN AW-7075) for small series
Tool steel (e.g. 1.2312) for larger quantities
Special composite materials for prototypes
Galvanically nickel-plated surfaces for improved wear resistance
3. Manufacturing process:
Base body:
CNC milling of the base body
Inserting the cooling channels by deep-hole drilling
Manufacturing the vacuum/compressed air channels
Producing the connections for media supply
Surface:
Smoothing the mold surface with fine milling cutters
Multi-stage grinding (grain size 120 to 1000)
Polishing to a mirror finish (Ra ≤ 0.2 µm)
Application of a hard material coating if required
Special processing:
Eroding of sharp inner edges
Laser texturing for special surface structures
Inserting of markings and alignment aids
Installation of temperature sensors
4. Quality assurance:
Metrological inspection:
3D coordinate measurement of all critical geometries
Surface roughness measurement
Inspection of the cooling channel geometry
Leak test of all media systems
Function test:
Test run with heating and cooling cycles
Inspection of the temperature distribution using a thermal imaging camera
Sample molding of samples
Documentation of all process parameters
5. Rework and optimization:
Fine tuning:
Adjustment of ventilation channels after test run
Optimization of cooling circuits
Repolishing of critical areas
Setting of optimal process parameters
Maintenance aspects:
Determination of maintenance intervals
Definition of wear limits
Creation of maintenance documentation
Training of operating personnel
Now the actual manufacturing process:
1. Material preparation:
Polycarbonate granulate is pre-dried at 120°C for at least 4 hours to remove any residual moisture.
Quality control of the granulate for purity and correct technical specifications.
Preparation of UV protection additives and other necessary additives.
2. Extrusion of the sheets:
The dried granules are fed into the extruder
Melting at 280-300°C under controlled conditions
Homogenization of the melt by screw conveying
Addition of UV stabilizers
Discharge through a slot die to form a sheet
Calibration of the sheet thickness by rollers
Controlled cooling over several cooling rollers
3. Thermoforming:
Cutting the sheets to the required size
Preheating the sheets to 185-195°C
Clamping them in the thermoforming frame
Vacuum or compressed air forming over a mold
Precise temperature and time control during the forming process
Controlled cooling to stabilize the shape
4. Finishing:
Cutting the edges to the final dimensions
Drilling mounting holes to specification
Deburring all edges
Cleaning the surfaces
Attaching seals or mounting profiles
5. Quality control:
Optical inspection for defects such as:
Bubbles or inclusions
Surface defects
Material discoloration
Dimensional inspection of all critical dimensions
Testing of material thickness at defined measuring points
Impact resistance tests on samples
UV transmission measurement
Leak test of the mounting points
6. packaging and storage:
Apply protective film on both sides
Dust-proof packaging
Storage under controlled conditions:
Temperature between 10-25°C
Humidity below 60%
Protected from direct sunlight
Special requirements for yurt skylights:
Increased UV resistance for outdoor use
Special geometry for optimal water drainage
Reinforced edge area for secure attachment
Additional insulation possible through double-wall construction
Customized opening mechanisms for ventilation
Critical process parameters
Precise temperature control in all process steps
Precise time control during thermoforming
Clean tools and dust-free environment
Continuous material control
Documentation of all process parameters for traceability
This detailed processes ensures the production of high-quality rooflights that meet the specific requirements for use in Yurts. Particularly important are UV resistance and dimensional stability in various weather conditions.
BTW - the costs for a mold alone are approx. 20K USD, for prototypes or very small series, you could also have a less expensive aluminum mold made without elaborate cooling for about 10K USD.
Do you believe, that a manufacturer is able to do it for one single piece, and are you willing to cover these costs?
I leave you now alone to find your conclusions for a solution.....
