DITAISteering column
covers.
Getting the
assembly right.
The customer sent us the metal frame. Our engineers fitted the steering-column covers to it and adjusted the CNC cutting in our workshop. Alongside a material change and a revised mounting approach, that hands-on work helped resolve the assembly concerns. The customer then approved the start of mass production.
The revised covers on the customer-supplied structure.
Working with the customer’s frame
We made four thermoformed covers for a compact electric delivery vehicle: the upper and rear handlebar covers, and the left and right steering-column covers. They enclosed the column and formed part of the vehicle’s exterior.
The long covers needed to meet the frame’s mounting points and align with the cover above. Having the customer’s metal structure in our workshop gave us a way to work on those relationships directly. We could take on the fitting and cutting adjustments here, with the mating structure in front of us.
Understanding the fit concern
The customer’s sample review showed that the rear handlebar cover fitted well, while the long column covers needed attention.
Some mounting holes sat off-centre within their formed recesses. Hole spacing differed from the CAD model and varied between parts. The adjoining covers also showed alignment issues.
Our engineers considered these observations together. Their review identified the long, narrow geometry and the flexibility of the PE samples as important contributors to distortion after forming. Changes in the shell’s shape also affected CNC trimming and hole positioning.
The work therefore covered both the shell’s ability to hold its shape and the location of the mounting features.
Explaining the material change
The customer preferred to retain PE. The overall column-cover shape was also fixed, so a broad redesign was not an available route.
Our engineers recommended ABS for the long covers to provide a more rigid shell and reduce the distortion affecting this assembly. We explained why the material change mattered to the mounting problem. After considering the recommendation, the customer agreed.
The recommendation addressed this component’s geometry and fit requirements. The mounting details still needed work alongside it.
Locating from the top
The assembly discussion established a priority: the top of the cover needed to attach securely and align correctly. The proposed approach used this end as the reference for the mounting positions farther down the column.
With the top in its intended position, the remaining holes needed to meet the frame. This gave both teams a common reference for discussing the adjustment.
The review also proposed adding control dimensions to the drawing for the features that governed frame fit, so those requirements would be explicit for manufacturing.
The proposed approach used the top of the cover as the assembly reference. Original project drawing.
Room around the mounting hole
The formed recess provides room around the circular mounting hole. The arrow illustrates the proposed allowance for shrinkage.
The proposed change elongated the formed recess around the mounting hole along the length of the cover.
If the shell changed dimension during forming, the CNC-cut hole would have more room to fall within that recessed area. Its target position would still follow the frame’s mounting pattern.
The drawing shows a circular hole inside an elongated pocket. The pocket provides the allowance; the fastener hole does not become a long slot.
That distinction let the team address variation in the formed shell while keeping the required hole spacing as the machining target. The drawing illustrates how the hole could sit farther down within the recess to accommodate shrinkage.
Workshop fit review with the covers on the mating structure.
Checking the assembled fit
During CNC development, our engineers used sample fit on the supplied metal structure to guide the cutting adjustments. The mounting positions and the way the covers met could be reviewed on the assembly itself.
The photographs show the revised covers around that structure. The workshop video follows the mounting recesses along the cover, giving a closer view of the details discussed in the drawings.
A closer look at
the mounting details
The workshop footage follows the recesses along the cover. Play the clip to see the part from the top mounting area to the lower end.
Original workshop footage. Audio removed. This is a close-up demonstration, not a performance test.
The customer approved
the start of production.
After the material change and assembly-fit adjustments, the customer approved the start of mass production.
The customer provided the mating structure and agreed to revise the material choice. Our team completed the workshop fitting and CNC adjustments. Both sides contributed to reaching production approval.
Customer identity is withheld. This case documents fit development and approval to start production, rather than long-term performance validation.
Let’s look at
your assembly.
Share the cover model and the structure it needs to fit. Tell us which interfaces matter most and what must remain unchanged. We can discuss the material and mounting references with you before planning the next sample.
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