Milo 1.5 Desktop Mill

Frame Reinforcement and Material Selection

Summary

Explored options for stiffening the Milo 1.5 Desktop Mill frame using concrete or epoxy concrete mix. Both methods were considered for vibration absorption and structural integrity.

Key Points

• Epoxy concrete mix using playsand and 2-part epoxy.
• Concrete option using a custom countertop blend.
• Including a frame inside is beneficial for vibration absorption.
• Decision on material not yet finalized; considering both methods.

Concrete vs Epoxy Granite

Cost-effectiveness

• Concrete mix is cheaper than epoxy granite.
• Concrete requires less equipment for production.

Mechanical Properties

• Concrete offers similar or better mechanical properties, including dimensional stability and vibration damping.
• Concrete can be molded into various shapes and colors.
• Concrete requires less maintenance compared to epoxy granite.

Comparison

• Epoxy granite limitations: thin-walled parts, curing requirements, and weight.
• Concrete advantages: thinner sections, room temperature curing, denser mixtures.

Recommendation

• Choose a high-strength concrete mix for countertop applications.
• Optimize mixture for density and vibration damping.
• Ensure proper curing and finishing techniques.
• Consider reinforcement materials for enhanced mechanical properties.

Structural Enhancements

Overview

Designing a metal plate to distribute the 4080 beam load and secure points on the new base.

Parts

• Metal plate, 160mm wide.
• Aluminum rails, 2040mm lengths.
• 1010mm connectors.

Steps

1. Attach metal plate to center of base. 2. Attach aluminum rails to metal plate. 3. Connect aluminum rails with 1010mm connectors.

Notes

• Metal plate and aluminum rails help distribute load and provide secure attachment points.

Vertical Tower Design

Overview

Designing a vertical tower for the Z-axis to be molded and attached to the concrete base.

Parts

• Openbuilds 4080x260mm C-Beam (A & B, 60mm longer for 120mm clearance build).
• Openbuilds 4080x250mm C-Beam (C).
• Openbuilds 4080x120mm C-Beam (D).

Steps

1. Assemble y-axis first. 2. Align y-axis with vertical tower. 3. Attach y-axis to vertical tower. 4. Attach vertical tower to base.

Notes

• Ensure proper alignment of y-axis and vertical tower.
• Consider ball screw clearance in molded tower design.

Motor and Control System

Problem

Upgrading 8mm ball screw to 12mm and changing to servos requires a different control system.

Solution

• Research larger stepper motors if staying with Duet control.
• Evaluate servo control boards and operating systems if switching to servos.

Concrete and Epoxy Considerations

Summary

Concrete and epoxy options for casting CNC bases.

Key Points

• Concrete shrinks and cracks, leading to decoupling from the outer structure.
• Epoxy does not shrink appreciably and stays in contact with the structure.
• Epoxy requires stiff fillers for bulk stiffness.
• CSA cement does not shrink and achieves high compressive strengths rapidly.