A Custom Orthotics Insole For Both Feet

Print to the right size. You can try taking a picture of you foot to see which of these would work best for you.
When printing orthotic insoles in 95A TPU, your infill choice affects comfort, flexibility, and durability. Since you’re aiming for a part that must absorb impact but also provide support, here are the best practices:

🔧 General Guidelines

Infill %:

15–25% → Softer, more cushioned feel (good for shock absorption).

30–50% → Balanced comfort and support (common for functional insoles).

60–80% → Much stiffer, more like a firm orthopedic insert.

Infill Pattern:

Gyroid → Excellent for flexible parts, distributes pressure evenly, keeps elasticity.

Cubic (3D honeycomb) → Good compromise between strength and flexibility.

Grid / Lines → Stiffer, less springy, but faster to print.

Perimeters (walls):
At least 3–4 walls to ensure durability, since TPU flexing can delaminate thin shells.

Layer Height:
0.2–0.3 mm for a good balance of strength and print time.

For most orthotic insoles in 95A TPU, a gyroid infill at 25–35% with 3–4 walls is a strong starting point.
That gives cushioning but enough support to keep from bottoming out under body weight.

Recommended Print Settings for TPU Orthotic Insoles

1. Material Selection:

   • TPU Type: Use TPU with Shore hardness of 85A (softer, more cushioned) or 95A (firmer, more supportive). Examples include Covestro Addigy FPU 79A, colorFabb varioShore TPU, or BASF Elastollan.
   • Properties: TPU is ideal for insoles due to its flexibility, durability, shock absorption, and resistance to moisture and bacteria.

2. Printer Requirements:

   • Type: FDM printer with a direct drive extruder is preferred for TPU due to its flexibility, which can cause issues in Bowden extruders.
   • Build Plate: Minimum size of 250 x 250 mm to accommodate larger shoe sizes.
   • Examples: Bambu Labs A1 or Raise3D E2 are suitable for TPU printing.

3. Print Settings:

   • Nozzle Temperature: 220–250°C, depending on the TPU brand. For example, colorFabb varioShore TPU may require 190–240°C to manipulate foaming and porosity. Start at the lower end and adjust based on print quality.
   • Bed Temperature: 40–60°C. A heated bed helps adhesion, but avoid overheating to prevent warping. Use a PEI or glass bed with glue stick or painter’s tape for better adhesion.
   • Print Speed: 20–40 mm/s. Slower speeds reduce stringing and improve layer adhesion with flexible TPU.
   • Layer Height: 0.1–0.2 mm for detailed, smooth insoles. Thinner layers improve surface quality and comfort.
   • Infill: 10–30% with a gyroid or honeycomb pattern for a balance of flexibility and support. Adjust infill density to vary hardness (e.g., higher infill for firmer areas).
   • Retraction: Minimal or disabled (0–2 mm). TPU’s flexibility makes retraction tricky, so use a direct drive extruder and test to minimize stringing.
   • Cooling: Low or no cooling (0–30% fan speed). Excessive cooling can cause poor layer adhesion in TPU.
   • Flow Rate: 100–110%. Slightly increase flow to compensate for TPU’s elasticity and ensure solid prints.

4. Additional Settings:

   • Wall Thickness: 1.2–2 mm (3–5 perimeters) for durability without sacrificing flexibility.
   • Support Structures: Generally not needed for insoles due to their flat or gently curved design, but use sparingly for overhangs if required.
   • Brim or Raft: A 5–10 mm brim can improve bed adhesion, especially for larger insoles.
   • Variable Hardness: Some designs allow for different hardness zones (e.g., softer heel, firmer arch) by adjusting infill density or using specialized TPU like varioShore.

5. Post-Processing:

   • Smoothing: Sand or use a heat gun lightly to smooth surfaces for comfort, but avoid overheating to preserve TPU properties.
   • Cleaning: Remove any stringing with a hobby knife. Ensure the insole is free of debris for hygiene.
   • Testing: Check fit and comfort with a test print, as TPU from different brands (e.g., brand A vs. brand B 95A) may vary in hardness despite identical Shore ratings.

Higher infill density makes sense on Hockey skates such as the Vapor X3 size D if you have wider flatter feet for added firmness and support, especially with navicular pinching (a mid-level skate as such with a stiffer boot can feel unforgiving without proper cushioning). The 10D Vapor fit is narrower in the forefoot and heel compared to broader profiles like Fit 2 or 3, so boosting density could help distribute pressure better and reduce that right-foot irritation against the composite shell.

Based on typical recommendations for TPU 95A in custom orthotics and insoles, aim for 30-50% infill to strike a balance—firm enough for stability and energy transfer in skates (which demand more rigidity than casual shoes) but still flexible to avoid hot spots. Lower than that (like 10-20%) might feel too squishy and not alleviate the pinching, while going above 50% could make it overly stiff and less comfortable for extended ice time. For hockey specifically, insoles with targeted arch support (like in commercial options such as Bauer Aetrex or Superfeet Hockey) often emphasize cushioning under high-pressure areas like the navicular to prevent exactly this issue in flat feet. If your model allows, consider variable infill: higher (40-50%) under the arch and midfoot for navicular relief, tapering to 20-30% elsewhere for flexibility.

Test print a prototype at 35-40% to start, and adjust based on feel—maybe with a gyroid or cross infill pattern for even compression in flexible materials like TPU. If the pinching persists, baking the skates or adding targeted padding (like EVA foam) alongside the insole could help. (My tips on Hockey skates and why I made these files.)