REDUCE MANUFACTURING COSTS WITH BETTER GD&T
Axis GD&T Services
Our Mission
We help designers and manufacturers speak the same language, GD&T, so specs are clear and nothing gets lost in translation. Not every company needs a full time specialist. We fill that gap.
Problems we solve
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Assemblies don't fit together
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Suppliers constantly ask drawing questions
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Tolerances are tighter than necessary
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Good parts are being rejected
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Inspection requirements are unclear
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Legacy drawings need updating
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New engineers need GD&T guidance
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And more!
How we can save you money
Designers:
We improve drawings so assemblies fit right the first time. Poor dimensioning causes failed assemblies or good parts getting rejected for no reason. Our tolerance stack up analysis often lets you widen tolerances without losing function, cutting costs and improving yield.
Vendors:
We clarify drawing requirements before production starts. Unclear or overly tight GD&T causes scrap, rework, and lost machine time. A quick review often finds ways to cut cost while still meeting design intent.
Milo Del Bigio
GDTP S09-18540
Lead GD&T Specialist
Milo is one of fewer than 30 GDTP Seniors in Canada. He refines drawings, recommends datum structures, and runs tolerance stack up analyses, aligning design intent with what's actually manufacturable.
Video Case Studies
Past Projects
How to use the past projects section
Hover mouse over areas in a box
"Before" and "after" will be shown with a brief description
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Note: Drawings depicted are dissimilar recreations of actual projects. No IP is being shared in the drawings below. Some dimensions are removed for clarity.
Vessel
Issue: Drawing Compliance
This vessel was designed to withstand high pressures, however the drawing did not follow the rules set out by the ASME Y14.5 standards.
Notable items that required correction are:
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Missing geometric controls
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Missing tolerances
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Incorrect tolerance zone shapes
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Material modifiers that do not align with the requirements of a pressure vessel
A basic dimension needs a geometric control associated with it.
In this case, the designer decided to switch to a +/- tolerance.
A counterbore symbol was added.
The shape of the tolerance zone is a cylinder, so a diameter symbol is placed before the tolerance zone size.
The orientation of the pattern to the bore axis was determined to be more important than to the face, so the datum order was switched.
A parallelism was not sufficient to control the sealing surface.
The same flatness that was added to the datum feature A was added to this feature.
Without a geometric control, the datum A surface's form is controlled by the overall size of the part (rule #1)
This was insufficient for a sealing surface, so a flatness was added.
The shape of the tolerance zone is a cylinder, so a diameter symbol is placed before the tolerance zone size.
MMC is not the appropriate material modifier here, and no physical interference here is expected. One could argue LMC may be appropriate, however RFS was selected by the designer.
Without a geometric control, the OD has no connection to the ID, and a thin wall condition may occur.
An LMC was appropriate for the positional tolerance that was added, as wall thickness must be maintained.
Distance from OD edge to raised face edge was a less important relationship, than raised face edge to ID.
The designer decided a diameter tolerance, and positional tolerance were more appropriate.
The 6x chamfers is an acceptable callout, however none of the views made it clear where the 5th and 6th chamfer were.
View was changed to a cross section to aid with clarity.
The length of the raised face was not defined.
Outcome
The drawing changes were made, and the machine shop it was contracted to were happy with the drawing.
Housing
Issue: Datum Selection & Overly Tight Tolerances
This housing mated with a similar housing creating a gearbox. Each bearing bore supported a shaft with a gear. The company had an internal rule for gear alignment that said they could have 0.00X" of misalignment per 1" of tooth length.
The bearing positional tolerances were not designed with this rule in mind, so a very tight tolerance was chosen. This resulted in excess dimensional non-conformances on all shipments.
Notable changes are:
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Increasing the general tolerance zone
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Creating a relationship between the bearing bores of mating gears
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Creating tolerance zones using the 0.00X"/1" of tooth length rule
The new positional tolerance was selected to loosely control the pattern of bearing bores to the dowels.
The new upper segment was selected to loosely control the pattern of bearing bores to the dowels.
The lower segment controls the bearing bore to the mating gear's bearing bore. This tolerance was calculated based on allowable gear misalignment.
The new upper segment was selected to loosely control the pattern of bearing bores to the dowels.
The lower segment controls the bearing bore to the mating gear's bearing bore. This tolerance was calculated based on allowable gear misalignment.
The new upper segment was selected to loosely control the pattern of bearing bores to the dowels.
The lower segment controls the bearing bore to the mating gear's bearing bore. This tolerance was calculated based on allowable gear misalignment.
The new upper segment was selected to loosely control the pattern of bearing bores to the dowels.
The lower segment controls the bearing bore to the mating gear's bearing bore. This tolerance was calculated based on allowable gear misalignment.
The new upper segment was selected to loosely control the pattern of bearing bores to the dowels.
The lower segment controls the bearing bore to the mating gear's bearing bore. This tolerance was calculated based on allowable gear misalignment.
The new upper segment was selected to loosely control the pattern of bearing bores to the dowels.
The lower segment controls the bearing bore to the mating gear's bearing bore. This tolerance was calculated based on allowable gear misalignment.
The new upper segment was selected to loosely control the pattern of bearing bores to the dowels.
The lower segment controls the bearing bore to the mating gear's bearing bore. This tolerance was calculated based on allowable gear misalignment.
Outcome
Non-conformances decreased once new inspection scheme was implemented. Both designers and machine shop were happy with the changes, and the assembly continued to work as expected.